CA1049905A - Method for treating parts made of titanium or titanium alloy; and parts produced thereby - Google Patents
Method for treating parts made of titanium or titanium alloy; and parts produced therebyInfo
- Publication number
- CA1049905A CA1049905A CA206,318A CA206318A CA1049905A CA 1049905 A CA1049905 A CA 1049905A CA 206318 A CA206318 A CA 206318A CA 1049905 A CA1049905 A CA 1049905A
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- CA
- Canada
- Prior art keywords
- enclosure
- treatment
- oxygen
- titanium
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/10—Oxidising
- C23C8/12—Oxidising using elemental oxygen or ozone
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Chemical Treatment Of Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to a method for the treatment of parts, the surfaces of which contain titanium. The part to be treated is disposed inside an enclosure. A vacuum is created in said enclosure until the pressure in the latter ranges from 1 to 10-8 Torr. An amount of oxygen ranging from 0.1 cmc to 60 cmc per cm2 of surface to be treated is introduced into the enclosure, and then the enclosure is heated to a temperature ranging from 450°C to 880°C. After this treatment the part is coated with a surface layer consisting essentially of titanium oxides and having a thickness greater than 15 microns to improve the frictional properties thereof.
The invention relates to a method for the treatment of parts, the surfaces of which contain titanium. The part to be treated is disposed inside an enclosure. A vacuum is created in said enclosure until the pressure in the latter ranges from 1 to 10-8 Torr. An amount of oxygen ranging from 0.1 cmc to 60 cmc per cm2 of surface to be treated is introduced into the enclosure, and then the enclosure is heated to a temperature ranging from 450°C to 880°C. After this treatment the part is coated with a surface layer consisting essentially of titanium oxides and having a thickness greater than 15 microns to improve the frictional properties thereof.
Description
104~1905 The T~resent invention relates to a method for the treatment of mechanical parts, the outer surfaces of which contain titanium. Such parts include parts made of solid titanium, parts made of titanium alloys, and parts made of any material, but surface-coated with titanium or a titanium alloy.
Titanium is a metal which has advantageous properties.
In particular, it is light, substantially resistent to corrosion, and has good mechanical properties. ~lowever, titanium has a '~ serious drawback in that it has very poor frictional properties a surface containing titanium and seizes when it is caused to ? rub on a surface of another material, such as, steel, or on ~ another surface of titanium.
'~ As titanium is essential to advanced technological industries such as those dealing with space travel, consider-able efforts have been made to provide titanium with good frictional strength.
Promising results have been obtained, in particular by oxidation. In particular, it has been found that, by coating titanium or titanium alloy parts with an oxide coating, usually based on Tio2, some frictional strength was obtained.
To form the oxide coating, various methods have been used, such ~ -;; as anodic oxidation or heating in an oxiding atmosphere in an ~` enclosure. The results obtained however have never been com-~ pletely satisfactory, due to either the coats flaking off during ., .
the friction, or scale being generated on the surfaces of the parts.
Some workers have tried to remove such drawbacks :::.s ::~
by carrying out the treatment in a number of steps, for ~ -instance by producing a layer of scale on the surface of the part to be treated, through an oxidation in oxygen, and then ; heating the coated part in argcnto diffuse the scale coating F
into the body of the titanium part. Such a method, which, in ,t .~. - 1 - .
q~
,.:~ ~ .: `. :: , ~049905 the opi.nion of said workers, is difficult to operate on an industrial scale, however, has a further disadvant~ge in that it requires hiqh treating temperatures, of the order of about 900 C, which is much higher than the temperature generally . accepted for annealing titanium, and long treatments greater .
than 24 hours.
The present invention provides a method for use on a commercial scale for oxiding titanium and the alloys thereof, .
which avoids all the above disadvantages and gives very good results, such as have not previously been obtained in the field o resistance to seizing and wear.
; According to the present invention there lS provided . a method for treating a mechanical part, an outer surface of ~; which contains titanium for improving the frictional properties and the resistance of such parts to wearing and seizing which method comprises at least partially removing natural layer of '~!~.' ''' oxide which initially covers said outer surface which contains ,.:
titanium, heating the part, an enclosure inside which a vacuum ~ - .
", . . .
S ~ is created by a vacuum system over a limited period of time, `
: 20 ~ isolating the enclosure containing the part from the vacuum :system, introducing into said enclosure an amount of oxygen ::
strictly defined as a function of the outer surface of the part and heating said part in said enclosure to a temperature in the ; range from 450 C to 880 C, the pressure in the enclosure, before ::; the introduction of oxygen, ranging from 1 to 10 8 Torr, and the amount of oxygen inside the enclosure is defined according to an increasing function of the total outer surface of the part to be treated, said amount of oxygen ranging from 10 3 to 2.55 mg/cm ~.
30~ The oxidation treatment of the present invention is based on the following discovery:
: A test piece made of titanium and having an area S
.~
s - 2 -"
,,~ . ~ , . . .. .
is heate~, under con~litions oE temperature, pressure, ambience, and the like, which will be precisely defined hereinafter, in a fluid-tight furnace into which a weight Q of oxygen has been introduced. A layer then forms Oll the surface of the test piece, which layer consists mainly of titanium oxides. ~he experiment is repeated a number of times, while varyiny the ratio Q- of the weight of oxygen introduced to t~e total area of the part or parts treated. For all the parts treated in this way, the total hardness ~, the thickness of the layers formed within the time unit, and the coefficient of friction f of the test piece thus treated when the latter rubs on steel, are carefully measured for each experiment.
When the ratio ~- is plotted as abscissa and the value ~, ~, and f are plotted as ordinate on a system of axes suitably selected (Fig. 2), it will be seen that the three curves obtained merge in a single curve C (Fig. 2), the particular feature of which is that it presents a very high peak and a very narrow base.
This phenomenon directs one very naturally to the oxidation treatment of titanium according to the present inventon. It is a question of replacing at least partially, the natural oxide layer which coats any titanium part by the oxide layer obtained when the oxidation takes place according to the peak of the curve C of Fig. 2.
The treatment will be conformity with the present inventlon if it meets all the following requirements:
¦~ (1) the natural layer of oxide which covers any part of the outer titanium surface containing must be at least ~, ~;~ partially removed. The thickness removed should be greater than 2 microns;
Titanium is a metal which has advantageous properties.
In particular, it is light, substantially resistent to corrosion, and has good mechanical properties. ~lowever, titanium has a '~ serious drawback in that it has very poor frictional properties a surface containing titanium and seizes when it is caused to ? rub on a surface of another material, such as, steel, or on ~ another surface of titanium.
'~ As titanium is essential to advanced technological industries such as those dealing with space travel, consider-able efforts have been made to provide titanium with good frictional strength.
Promising results have been obtained, in particular by oxidation. In particular, it has been found that, by coating titanium or titanium alloy parts with an oxide coating, usually based on Tio2, some frictional strength was obtained.
To form the oxide coating, various methods have been used, such ~ -;; as anodic oxidation or heating in an oxiding atmosphere in an ~` enclosure. The results obtained however have never been com-~ pletely satisfactory, due to either the coats flaking off during ., .
the friction, or scale being generated on the surfaces of the parts.
Some workers have tried to remove such drawbacks :::.s ::~
by carrying out the treatment in a number of steps, for ~ -instance by producing a layer of scale on the surface of the part to be treated, through an oxidation in oxygen, and then ; heating the coated part in argcnto diffuse the scale coating F
into the body of the titanium part. Such a method, which, in ,t .~. - 1 - .
q~
,.:~ ~ .: `. :: , ~049905 the opi.nion of said workers, is difficult to operate on an industrial scale, however, has a further disadvant~ge in that it requires hiqh treating temperatures, of the order of about 900 C, which is much higher than the temperature generally . accepted for annealing titanium, and long treatments greater .
than 24 hours.
The present invention provides a method for use on a commercial scale for oxiding titanium and the alloys thereof, .
which avoids all the above disadvantages and gives very good results, such as have not previously been obtained in the field o resistance to seizing and wear.
; According to the present invention there lS provided . a method for treating a mechanical part, an outer surface of ~; which contains titanium for improving the frictional properties and the resistance of such parts to wearing and seizing which method comprises at least partially removing natural layer of '~!~.' ''' oxide which initially covers said outer surface which contains ,.:
titanium, heating the part, an enclosure inside which a vacuum ~ - .
", . . .
S ~ is created by a vacuum system over a limited period of time, `
: 20 ~ isolating the enclosure containing the part from the vacuum :system, introducing into said enclosure an amount of oxygen ::
strictly defined as a function of the outer surface of the part and heating said part in said enclosure to a temperature in the ; range from 450 C to 880 C, the pressure in the enclosure, before ::; the introduction of oxygen, ranging from 1 to 10 8 Torr, and the amount of oxygen inside the enclosure is defined according to an increasing function of the total outer surface of the part to be treated, said amount of oxygen ranging from 10 3 to 2.55 mg/cm ~.
30~ The oxidation treatment of the present invention is based on the following discovery:
: A test piece made of titanium and having an area S
.~
s - 2 -"
,,~ . ~ , . . .. .
is heate~, under con~litions oE temperature, pressure, ambience, and the like, which will be precisely defined hereinafter, in a fluid-tight furnace into which a weight Q of oxygen has been introduced. A layer then forms Oll the surface of the test piece, which layer consists mainly of titanium oxides. ~he experiment is repeated a number of times, while varyiny the ratio Q- of the weight of oxygen introduced to t~e total area of the part or parts treated. For all the parts treated in this way, the total hardness ~, the thickness of the layers formed within the time unit, and the coefficient of friction f of the test piece thus treated when the latter rubs on steel, are carefully measured for each experiment.
When the ratio ~- is plotted as abscissa and the value ~, ~, and f are plotted as ordinate on a system of axes suitably selected (Fig. 2), it will be seen that the three curves obtained merge in a single curve C (Fig. 2), the particular feature of which is that it presents a very high peak and a very narrow base.
This phenomenon directs one very naturally to the oxidation treatment of titanium according to the present inventon. It is a question of replacing at least partially, the natural oxide layer which coats any titanium part by the oxide layer obtained when the oxidation takes place according to the peak of the curve C of Fig. 2.
The treatment will be conformity with the present inventlon if it meets all the following requirements:
¦~ (1) the natural layer of oxide which covers any part of the outer titanium surface containing must be at least ~, ~;~ partially removed. The thickness removed should be greater than 2 microns;
(2) the parts to be treated are put in a fluid- !
tight furnace in which the pressure has been lowered to a value _ 3 _ in th~ ran~Je ~rom 1 to 10 8 Torr, before introducing an amount Q of oxygen strictly defined as a function of the total area S of the parts to be treated. If Q is expressed ln milligramB
and S is expressed in square centimetre the ratio Q- according to which the treatment according to the invention is carried out will range from 10 to 2.55 milligrams per square centimetre; and
tight furnace in which the pressure has been lowered to a value _ 3 _ in th~ ran~Je ~rom 1 to 10 8 Torr, before introducing an amount Q of oxygen strictly defined as a function of the total area S of the parts to be treated. If Q is expressed ln milligramB
and S is expressed in square centimetre the ratio Q- according to which the treatment according to the invention is carried out will range from 10 to 2.55 milligrams per square centimetre; and
(3) the temperature of treatment is in the range :
O ~ . r -450 C to 880 C. ;
According to a particular embodiment of the invention -~
-the sequence of steps is as follows: ~ :
(a) the natural layer of oxide which coats the parts to be treated is partially removed;
(b) the parts are disposed in an enclosure connected :`
~": ,~ : . , , ~ to a vacuum system; : ~ .
, (c) a vacuum is created in said enclosure such that .
~ the:pressure therein ranges from 1 to 10 8 Torr;
.~ (d) the enclosure is isolated from the vacuum system; : ~.
(e) an amount of oxygen defined as a function of ~ the totaL outer area of the parts to be treated contained in .; 1 the~enclosure is introduced into the enclosure; ~ :
(f) the enclosure containing the parts is heated - 1 to a temperature ranging from 450 C to 880 C.
Accorùlng to another embodiment of the invention, ; the~creatlon of vacuum is carried out at any time after the temperature of the enclosure is brought to a temperature higher thàn:the ambient temperature, in which case the sequence of opera~tions becomes: -(a) Removal, at least partially, of the natural ;30~ layer of oxlde, (b) Disposing the parts inside the enclosure, ~~
(c) Starting the heating syseem, , . . .
. ~ .
~ - 4 -i .~.. , .... , ~ ... .. .......
(d) Cre~ting a vacuum, and then isolating the enclosure, and (e) Introducing the oxygen.
According to another embodiment of the invention, the oxygen required for the treatment may be supplied by any means whatever, such as, a gas directly injected into the enclosure, by means of a substance capable of releasing oxygen at the -temperature such as an oxide, or by degassing a body which has previously absorbed some oxygen.
According to another embodiment of the invention, the oxygen is not introduced in total at the beginning of the treat-ment, but is introduced over the whole period of treatment, either continuously or batchwise, after the vacuum is created in the enclosure.
According to another embodiment of the invention, the cooling of the parts takes place slowly inside the enclosure, that is, by stopping heating said enclosure. -According to another embodiment of the invention, the parts are rapidly cooled, either inside or outside the enclosure.
A part according to the invention, the outer surface of which initially contains titanium, after being treated, is coated with a surface layer consisting mainly of titanium oxides and having a thickness greater than 10 microns.
The amount of oxygen duly determined as a function of the total area of the parts to be treated thus may be the only gas present in the enclosure during the treatment. However, as a filler gas, a rare gas should preferably be chosen, argon being particularly suitable, and it is advantageous to calculate the amount of said filler gas so that, after expansion, the gas pressure inside the enclosure is substantially equal to atmos-pheric pressure.
In the treatment of the present invention a variation of the ratio Q- with time is possible provided that the values ... . . .
~049905 reached by s~id ratio pass throu~h the area of the peak of curve C during the period of treatment.
According to another feature of the invention, the ; temperature and the time of treatment of a part are determined -~
from a diagram, the coordinates of which are the times of treat-ment and the temperatures of treatment, so as to correspon~ to a point lying inside an area included between two limit curves -~ ;
which define the requirements to be met to obtain a surface layer with a thickness sufficient to enable the titanium as treated to '~
rub without seizing.
The layer produced by the treatment according to the invention has unique and outstanding properties namely; i~
(1) the adhesion of said layer to the support is quite outstanding, as a result of the original morphology of the "hitching" area, where there is no break of continuity. Passing from an area consisting mainly of oxide to a lower layer consist-ing mainly of titanium takes place with a uniform gradient, due ~`
to an inter-diffusion between the two bodies.
(2) In contradistinction with all the other known ~ 20 layers of oxide, no residual tensile stress appears, which pro- -:. :
~ vides the treatment according to the invention with the Y ~ advantageous property of only very slightly affecting the resistance of the parts to strain. This property results from the fact that the total hardness ~ of the layer has a minimum .
value at the peak of curve C.
(3) The friction coefflcient may surprisingly fall ; to the very low value of 0.07 on steel parts, this without the addition of any lubricant.
O ~ . r -450 C to 880 C. ;
According to a particular embodiment of the invention -~
-the sequence of steps is as follows: ~ :
(a) the natural layer of oxide which coats the parts to be treated is partially removed;
(b) the parts are disposed in an enclosure connected :`
~": ,~ : . , , ~ to a vacuum system; : ~ .
, (c) a vacuum is created in said enclosure such that .
~ the:pressure therein ranges from 1 to 10 8 Torr;
.~ (d) the enclosure is isolated from the vacuum system; : ~.
(e) an amount of oxygen defined as a function of ~ the totaL outer area of the parts to be treated contained in .; 1 the~enclosure is introduced into the enclosure; ~ :
(f) the enclosure containing the parts is heated - 1 to a temperature ranging from 450 C to 880 C.
Accorùlng to another embodiment of the invention, ; the~creatlon of vacuum is carried out at any time after the temperature of the enclosure is brought to a temperature higher thàn:the ambient temperature, in which case the sequence of opera~tions becomes: -(a) Removal, at least partially, of the natural ;30~ layer of oxlde, (b) Disposing the parts inside the enclosure, ~~
(c) Starting the heating syseem, , . . .
. ~ .
~ - 4 -i .~.. , .... , ~ ... .. .......
(d) Cre~ting a vacuum, and then isolating the enclosure, and (e) Introducing the oxygen.
According to another embodiment of the invention, the oxygen required for the treatment may be supplied by any means whatever, such as, a gas directly injected into the enclosure, by means of a substance capable of releasing oxygen at the -temperature such as an oxide, or by degassing a body which has previously absorbed some oxygen.
According to another embodiment of the invention, the oxygen is not introduced in total at the beginning of the treat-ment, but is introduced over the whole period of treatment, either continuously or batchwise, after the vacuum is created in the enclosure.
According to another embodiment of the invention, the cooling of the parts takes place slowly inside the enclosure, that is, by stopping heating said enclosure. -According to another embodiment of the invention, the parts are rapidly cooled, either inside or outside the enclosure.
A part according to the invention, the outer surface of which initially contains titanium, after being treated, is coated with a surface layer consisting mainly of titanium oxides and having a thickness greater than 10 microns.
The amount of oxygen duly determined as a function of the total area of the parts to be treated thus may be the only gas present in the enclosure during the treatment. However, as a filler gas, a rare gas should preferably be chosen, argon being particularly suitable, and it is advantageous to calculate the amount of said filler gas so that, after expansion, the gas pressure inside the enclosure is substantially equal to atmos-pheric pressure.
In the treatment of the present invention a variation of the ratio Q- with time is possible provided that the values ... . . .
~049905 reached by s~id ratio pass throu~h the area of the peak of curve C during the period of treatment.
According to another feature of the invention, the ; temperature and the time of treatment of a part are determined -~
from a diagram, the coordinates of which are the times of treat-ment and the temperatures of treatment, so as to correspon~ to a point lying inside an area included between two limit curves -~ ;
which define the requirements to be met to obtain a surface layer with a thickness sufficient to enable the titanium as treated to '~
rub without seizing.
The layer produced by the treatment according to the invention has unique and outstanding properties namely; i~
(1) the adhesion of said layer to the support is quite outstanding, as a result of the original morphology of the "hitching" area, where there is no break of continuity. Passing from an area consisting mainly of oxide to a lower layer consist-ing mainly of titanium takes place with a uniform gradient, due ~`
to an inter-diffusion between the two bodies.
(2) In contradistinction with all the other known ~ 20 layers of oxide, no residual tensile stress appears, which pro- -:. :
~ vides the treatment according to the invention with the Y ~ advantageous property of only very slightly affecting the resistance of the parts to strain. This property results from the fact that the total hardness ~ of the layer has a minimum .
value at the peak of curve C.
(3) The friction coefflcient may surprisingly fall ; to the very low value of 0.07 on steel parts, this without the addition of any lubricant.
(4) The sensitivity of titanium to seizure, which is greatly feared in the engineering industry, has disappeared, even under very heavy load conditions.
The present invention will be further illustrated by :
'~ , ~ .
!_ . .
;' .' ... , . . ~ . ': ' ' way of the accompanyinc3 drawings in which:
Fig. 1 is a sectional view giving a diagrammatic representation of an enclosure for carrying out the method according to one embodiment of the present invention, Fig. 2 is a graph showing the variation of the thick-ness E of the surface layer, of the friction coefficient f, and ~ -of the total hardness ~, as a function of the amount of oxygen .~ ~
introduced per unit area, the curves ~, f, and ~ merging in a single curve C, and Fig. 3 is a diagram which indicates the times of treatment as a function of the temperature, so as to obtain a .
non-pulverulent layer sufficiently thick capable without seizing. ~f~
Referring an embodiment of the drawings and partic- ~-ularly Fig. 1 part 2 to be treated is disposed inside the enclosure 1. The part 2 may be of solid titanium, or of titanium alloy, or may be covered with titanium or a titanium alloy. The enclosure 1 is provided with electric resistors 3 heating means, _~
which provided as varying the temperature inside the enclosure with accuracy, as the method is being carried out.
, The vacuum system 6 such as a pump is connected to r~ the inner space of the enclosure 1, a line 4 is provided for the~ supply of oxygen, and, a line S is provided for supplying an inert gas,; such as argon, in the direction of the arrow 7.
After the treatment is completed, the surface of ; the part 2 is found to be covered with a layer consisting mainly of titanium oxides, the characteristics of which are illustrated in the graph of Fig. 2. This graph illustrates, as a function '~ ;; of the ratio Q-, the variations of the friction coefficient f, the hardness ~, expressed in Vickers units, and the thickness 30~ r of~the surface layer obtained after treating a part made of a titanlum alloy. The figures vary with the nature of the basic r part. But, when the method according to the invention is duly , followed, the relativity of said variation remains similar for any titanium-containing part: the curves ~, f and ~ are merged in a curve C. , The present invention will be further illustrated by way of the following examples.
~ "Faville" type tests --~ Example 1 .-This type of test is carried out on a Faville-Levally, in which a cylinder of a diameter of 6.5 mm and a height of 40 mm, the surface S of which is equal to 9.35 cm , is rotated bet-ween two jaws out as V's having 90 angles: a load which incre-~, ~
ases linearly as a function of time is applied on the jaws.
The test is carried out in the ambient air. A testpart made of titanium or titanium alloy and conventionally oxidized, for instance in a bath of sulfuric acid at ambient temperature with a current~density of 0.3 A/dm2 during 20 mn, seizes practlcally~instantaneously between steel jaws, while a _ test part treated by the method according to the invention, that is,~havlng first being subjected to~a sanding operation in order ~20~ to remove the~natural layer of oxide on a depth of 2.5 microns, and~then~heated~to~650C for 8 hours (point 30, Fig. 3) in a furnace contaInlng~l2~mg;of~oxygen, so as to provide a ratio Q~
equal~to 2.29 (point 31, Fig. 2), the auxiliary gas being argon, can rub under a load of 600 daN without any seizing occuring.
In thl~s~case;~the~coefficlent of friction throughout the test remain~s below 0.12.
Example 2 Tests~were carried out with test parts of the "Faville" type,~treated under~the same conditions as in the 30~ Example~1, but~with an amount of oxygen equal to 32 mg. Under such conditions the initial ratio S is equal to 3.42 mg/cm .
Because of leaks in the furnace, a ratio 8 equal to ~ -, ! d~ ~ , . ~
' , ', .';.`, ': ' ' , - , , ' ' 0.07 mt3.cm was reached at the end of the treatment, that is, after 8 hours at 650C, which mcans that the curve C as shown in Fig. 2 was followed. Thus, during the period of treatment, the ratio 8 passed through the area of the peak P of the curve C of Fig. 2.
With test parts treated in this way, results are obtained which are in conformity with the invention. Indeed, i-said results are not exactly as good as if said ratio ~- had kept ranging from O.ll to 2.55 milligrams per square centimetre ;` lO during the whole duration of the treatment. They are, however; definitely better than the results obtained with conventionalmethods. In particular, a load of 600 daN can be reached without any seizing, with a coefficient of friction equal to O.lS.
Test on a cylindrical friction machine working on a flat surface.
Example 3 A ring of titanium or titanium alloy, having a dia-meter of 35 MM and a height of 20 mm, and a speed of rotation of 1200 r.p.m., rubs on a steel plate in the shape of a parall-elepiped, the dimensions of which are 30 x 18 x 8 mm. An ;
. . :
increasing load varying from 0 to 600 daN within 3 mn 20 s. is applied to the plate.
After the maximal lead of 600 daN is reached, the : :
test is carried on at said maximum load. The test is effected in pure and neutral vaseline oil.
A ring of titanium or titanium alloy, treated by conventional treatment of anodic oxidation mentioned herein- -~
above, seizes as soon as the load reaches 80 daN, while a ring treated by the method according to the invention, as explained i :~ ~ " -in Example l (650C, 8 h; 1.29 mg/cm ) may reach the load of 600 daN and rotate for 2 hours under said load without any r trace of seizing.
_ g _ ~: :
~- . .. . :.. , .:. . ::
-- Wearing test ~
Example 4 A type of test in which a titanium or titanium alloy ring, having an outer diameter of 60 mm and a speed of rotation of 100 r.p.m., is caused to rub on the hemispheric end of a ball made of 100 C 6 steel, the radius of curvature of said end being equal to 6 mm. A constant load equal to 5 daN is applied to said ball.
An anodically oxided ring is able to rotate only for two hours, while regularly losing 12 mg every 30 mn, whereas with a test part treated according to the invention as pre-viously described the results are multiplied by 100, and it is p .
p~ssible to rotate for more than 10 hours: at the end of this latter period of time, only a minimum wear is obtained, which reaches only about 2.5 mg.
Original methods of procedure for the oxidation treatment for titanium and the alloys thereof proceed from the number of technologies as adapted to such or such case. Any ~ ;
technoIogy of treatment which complies accurately and together f ~ 20 ~ ~with the four features of treatment according to the invention is~ln conformity~with the invention.
. ,.,~
n an example thereof:
~ A~part~was taken from an UTA6V alloy of titanium f~ containlng 6~f alumlnium and 4% vanadium. The part is a test part of the "Faville" type, with a diameter of 6.5 cm, a height of 4~0~mm, and an area of 9.35 cm2. The part was sanded for r 2 mn~in an apparatus supplied under the trade mark "Vapor B~last", under a jet pressure of 5 bars. The particle size of the abrasive was 4 microns. Upon completion of the sanding 30 ~ ~operation, the part was quickly disposed inside the enclosure of a fluid-tight vacuum furnace of stainless steel, with a diameter of 104 mm, a length of 965 mm, and a volume equal to ;,:
.,: .
, -- 1 0 --: :
. ~4 -.
- .
8.275 dm3. rrherca~ter the vacuum system was started till the pressure in the furnace ranges from 10 5 and lO 6 Torr. The pumping enclosure was isolated, and then the heating system was started till the part was brought to a temperature of 600~C in the furnace. During the raising of the temperature, an amount of oxygen equal to 16.8 mg (1.8 mg/cm2 of area to be treated) was introduced. Then auxiliary argon was introduced till a total pressure of 400 Torr in the enclosure was obtained. After keeping the parts for lO hours at 600c in the enclosure (point 28, line 24, Fig. 3), the enclosure was allowed to cool down to about 100C, and the part was removed. The layer obtained by the treatment is a layer consisting essentially of titanium oxide, Tio2. Its thickness is about 24 microns. Its average hardness is 500 Vickers under 15 grams.
If a test of the Faville type as described hereinabove is carried out, with jaws of carbon steel (XC 35) containing 0.35~ of carbon, the following results are obtained:
At the start, a very low coefficient of friction of about 0.05 is observed. Then, as the load increases, the co-efficient of friction increases slightly to stabilize itselfat a value of 0.075. At the end of the test, that is, after 40 seconds of operation, it can be noted that the test part creeps under a load of 540 daN. ;
After the test the friction area is absolutely smooth.
,~ Weighing the test part before and after the test shows that the , wear is lower than l mg, that is, may be considered as zero in ~-the practice. By way of comparison, a test carried out with an untreated test part leads to instantaneous seizing.
It will be noted that the method defined in the above example conforms stirctly to the invention in that it comprises the four features of the invention. r ~:
As a matter of fact:
~ ~9 - '.
---` 1049905 (1) the natural oxide l~yer which covers the part before the treatment is duly partially removed, due to the sand- -ing operation;
(2) an amount of oxygen Q which, according to the invention, is such that the ratio Q- ranges from 0.11 and 2.55 milligrams per square centimetre is duly introduced in the fluid-tight furnace;
~ (3) the process of oxidation occurs duly only in the '~ presence of the total amount of oxygen required and a rare gas contained in an i.e. argon, in the present example;
(4) the temperature ranges duly from 450C to 880C.
But this example of a practical method of procedure is given only as a non-restrictive one, as any method of oxidation of titanium or titanium alloys which complies with the ."
joint four features of the treatment according to the invention would be a method of procedure proceeding from the invention.
Thus, while complying with the determined limits for the amount of oxygen introduced, there is shown in Fig. 3 the area of treatment for titanium parts, which ar~ ils limited by the curves 21 and 22.
~J ~
A first example is given by the parts treated at a temperature of 600C. The line 24, which corresponds to said treating temperature and is plotted at the ordinate 600C on the d~lagram of Fig. 3, passes through the hatched area A
accordlng to a period of treating time bound by the two lines 25 and~26, which correspond to treating times of 3 1/2 h and 12 1/2 h respectlvely. The part will therefore be treated within said period of time. Keeping the part at 600C for more thàn 12 1/2 h would result in a pulverent layer, while keeping ~ said part at 600C for less than 3 1/2 h would give a layer, the thickness of which would be too small to allow rubbing r correctly. An amount of oxygen per unit area of part to be ~ ~ .
,, .
' `` 1049905 treated t~iclher th~n 2.55 my/cm would ]ead to a layer thickness smaller than that which can be obtained with the amount of oxygen according to the invention, and to a coefficient of friction de~initely higher than 0.07; an amount of oxygen per unit area of part to be treated lower than 10 3 mg/cm2 would result in a layer, the thickness of which would be too small to rub correctly.
.
A second example is given for a part treated at a temperature of 700C. The line 27, which corresponds to said treating temperature and is plotted at the ordinate 700C on I~ the diagram of Fig. 3, passes through the hatched area 3 accord-¦~ ing to a period of treating time ranging from 15 minutes to 5 ~-hours. The part will thus be treated within said period of ~;~ time to obtain the qualities defined hereinabove, with an ~
i amount of oxygen still ranging from 10 3 to 2.55 mg/cm2. ~ -,. .... .
~ -, ~ - 13 -:
,. , ~ ., :,
The present invention will be further illustrated by :
'~ , ~ .
!_ . .
;' .' ... , . . ~ . ': ' ' way of the accompanyinc3 drawings in which:
Fig. 1 is a sectional view giving a diagrammatic representation of an enclosure for carrying out the method according to one embodiment of the present invention, Fig. 2 is a graph showing the variation of the thick-ness E of the surface layer, of the friction coefficient f, and ~ -of the total hardness ~, as a function of the amount of oxygen .~ ~
introduced per unit area, the curves ~, f, and ~ merging in a single curve C, and Fig. 3 is a diagram which indicates the times of treatment as a function of the temperature, so as to obtain a .
non-pulverulent layer sufficiently thick capable without seizing. ~f~
Referring an embodiment of the drawings and partic- ~-ularly Fig. 1 part 2 to be treated is disposed inside the enclosure 1. The part 2 may be of solid titanium, or of titanium alloy, or may be covered with titanium or a titanium alloy. The enclosure 1 is provided with electric resistors 3 heating means, _~
which provided as varying the temperature inside the enclosure with accuracy, as the method is being carried out.
, The vacuum system 6 such as a pump is connected to r~ the inner space of the enclosure 1, a line 4 is provided for the~ supply of oxygen, and, a line S is provided for supplying an inert gas,; such as argon, in the direction of the arrow 7.
After the treatment is completed, the surface of ; the part 2 is found to be covered with a layer consisting mainly of titanium oxides, the characteristics of which are illustrated in the graph of Fig. 2. This graph illustrates, as a function '~ ;; of the ratio Q-, the variations of the friction coefficient f, the hardness ~, expressed in Vickers units, and the thickness 30~ r of~the surface layer obtained after treating a part made of a titanlum alloy. The figures vary with the nature of the basic r part. But, when the method according to the invention is duly , followed, the relativity of said variation remains similar for any titanium-containing part: the curves ~, f and ~ are merged in a curve C. , The present invention will be further illustrated by way of the following examples.
~ "Faville" type tests --~ Example 1 .-This type of test is carried out on a Faville-Levally, in which a cylinder of a diameter of 6.5 mm and a height of 40 mm, the surface S of which is equal to 9.35 cm , is rotated bet-ween two jaws out as V's having 90 angles: a load which incre-~, ~
ases linearly as a function of time is applied on the jaws.
The test is carried out in the ambient air. A testpart made of titanium or titanium alloy and conventionally oxidized, for instance in a bath of sulfuric acid at ambient temperature with a current~density of 0.3 A/dm2 during 20 mn, seizes practlcally~instantaneously between steel jaws, while a _ test part treated by the method according to the invention, that is,~havlng first being subjected to~a sanding operation in order ~20~ to remove the~natural layer of oxide on a depth of 2.5 microns, and~then~heated~to~650C for 8 hours (point 30, Fig. 3) in a furnace contaInlng~l2~mg;of~oxygen, so as to provide a ratio Q~
equal~to 2.29 (point 31, Fig. 2), the auxiliary gas being argon, can rub under a load of 600 daN without any seizing occuring.
In thl~s~case;~the~coefficlent of friction throughout the test remain~s below 0.12.
Example 2 Tests~were carried out with test parts of the "Faville" type,~treated under~the same conditions as in the 30~ Example~1, but~with an amount of oxygen equal to 32 mg. Under such conditions the initial ratio S is equal to 3.42 mg/cm .
Because of leaks in the furnace, a ratio 8 equal to ~ -, ! d~ ~ , . ~
' , ', .';.`, ': ' ' , - , , ' ' 0.07 mt3.cm was reached at the end of the treatment, that is, after 8 hours at 650C, which mcans that the curve C as shown in Fig. 2 was followed. Thus, during the period of treatment, the ratio 8 passed through the area of the peak P of the curve C of Fig. 2.
With test parts treated in this way, results are obtained which are in conformity with the invention. Indeed, i-said results are not exactly as good as if said ratio ~- had kept ranging from O.ll to 2.55 milligrams per square centimetre ;` lO during the whole duration of the treatment. They are, however; definitely better than the results obtained with conventionalmethods. In particular, a load of 600 daN can be reached without any seizing, with a coefficient of friction equal to O.lS.
Test on a cylindrical friction machine working on a flat surface.
Example 3 A ring of titanium or titanium alloy, having a dia-meter of 35 MM and a height of 20 mm, and a speed of rotation of 1200 r.p.m., rubs on a steel plate in the shape of a parall-elepiped, the dimensions of which are 30 x 18 x 8 mm. An ;
. . :
increasing load varying from 0 to 600 daN within 3 mn 20 s. is applied to the plate.
After the maximal lead of 600 daN is reached, the : :
test is carried on at said maximum load. The test is effected in pure and neutral vaseline oil.
A ring of titanium or titanium alloy, treated by conventional treatment of anodic oxidation mentioned herein- -~
above, seizes as soon as the load reaches 80 daN, while a ring treated by the method according to the invention, as explained i :~ ~ " -in Example l (650C, 8 h; 1.29 mg/cm ) may reach the load of 600 daN and rotate for 2 hours under said load without any r trace of seizing.
_ g _ ~: :
~- . .. . :.. , .:. . ::
-- Wearing test ~
Example 4 A type of test in which a titanium or titanium alloy ring, having an outer diameter of 60 mm and a speed of rotation of 100 r.p.m., is caused to rub on the hemispheric end of a ball made of 100 C 6 steel, the radius of curvature of said end being equal to 6 mm. A constant load equal to 5 daN is applied to said ball.
An anodically oxided ring is able to rotate only for two hours, while regularly losing 12 mg every 30 mn, whereas with a test part treated according to the invention as pre-viously described the results are multiplied by 100, and it is p .
p~ssible to rotate for more than 10 hours: at the end of this latter period of time, only a minimum wear is obtained, which reaches only about 2.5 mg.
Original methods of procedure for the oxidation treatment for titanium and the alloys thereof proceed from the number of technologies as adapted to such or such case. Any ~ ;
technoIogy of treatment which complies accurately and together f ~ 20 ~ ~with the four features of treatment according to the invention is~ln conformity~with the invention.
. ,.,~
n an example thereof:
~ A~part~was taken from an UTA6V alloy of titanium f~ containlng 6~f alumlnium and 4% vanadium. The part is a test part of the "Faville" type, with a diameter of 6.5 cm, a height of 4~0~mm, and an area of 9.35 cm2. The part was sanded for r 2 mn~in an apparatus supplied under the trade mark "Vapor B~last", under a jet pressure of 5 bars. The particle size of the abrasive was 4 microns. Upon completion of the sanding 30 ~ ~operation, the part was quickly disposed inside the enclosure of a fluid-tight vacuum furnace of stainless steel, with a diameter of 104 mm, a length of 965 mm, and a volume equal to ;,:
.,: .
, -- 1 0 --: :
. ~4 -.
- .
8.275 dm3. rrherca~ter the vacuum system was started till the pressure in the furnace ranges from 10 5 and lO 6 Torr. The pumping enclosure was isolated, and then the heating system was started till the part was brought to a temperature of 600~C in the furnace. During the raising of the temperature, an amount of oxygen equal to 16.8 mg (1.8 mg/cm2 of area to be treated) was introduced. Then auxiliary argon was introduced till a total pressure of 400 Torr in the enclosure was obtained. After keeping the parts for lO hours at 600c in the enclosure (point 28, line 24, Fig. 3), the enclosure was allowed to cool down to about 100C, and the part was removed. The layer obtained by the treatment is a layer consisting essentially of titanium oxide, Tio2. Its thickness is about 24 microns. Its average hardness is 500 Vickers under 15 grams.
If a test of the Faville type as described hereinabove is carried out, with jaws of carbon steel (XC 35) containing 0.35~ of carbon, the following results are obtained:
At the start, a very low coefficient of friction of about 0.05 is observed. Then, as the load increases, the co-efficient of friction increases slightly to stabilize itselfat a value of 0.075. At the end of the test, that is, after 40 seconds of operation, it can be noted that the test part creeps under a load of 540 daN. ;
After the test the friction area is absolutely smooth.
,~ Weighing the test part before and after the test shows that the , wear is lower than l mg, that is, may be considered as zero in ~-the practice. By way of comparison, a test carried out with an untreated test part leads to instantaneous seizing.
It will be noted that the method defined in the above example conforms stirctly to the invention in that it comprises the four features of the invention. r ~:
As a matter of fact:
~ ~9 - '.
---` 1049905 (1) the natural oxide l~yer which covers the part before the treatment is duly partially removed, due to the sand- -ing operation;
(2) an amount of oxygen Q which, according to the invention, is such that the ratio Q- ranges from 0.11 and 2.55 milligrams per square centimetre is duly introduced in the fluid-tight furnace;
~ (3) the process of oxidation occurs duly only in the '~ presence of the total amount of oxygen required and a rare gas contained in an i.e. argon, in the present example;
(4) the temperature ranges duly from 450C to 880C.
But this example of a practical method of procedure is given only as a non-restrictive one, as any method of oxidation of titanium or titanium alloys which complies with the ."
joint four features of the treatment according to the invention would be a method of procedure proceeding from the invention.
Thus, while complying with the determined limits for the amount of oxygen introduced, there is shown in Fig. 3 the area of treatment for titanium parts, which ar~ ils limited by the curves 21 and 22.
~J ~
A first example is given by the parts treated at a temperature of 600C. The line 24, which corresponds to said treating temperature and is plotted at the ordinate 600C on the d~lagram of Fig. 3, passes through the hatched area A
accordlng to a period of treating time bound by the two lines 25 and~26, which correspond to treating times of 3 1/2 h and 12 1/2 h respectlvely. The part will therefore be treated within said period of time. Keeping the part at 600C for more thàn 12 1/2 h would result in a pulverent layer, while keeping ~ said part at 600C for less than 3 1/2 h would give a layer, the thickness of which would be too small to allow rubbing r correctly. An amount of oxygen per unit area of part to be ~ ~ .
,, .
' `` 1049905 treated t~iclher th~n 2.55 my/cm would ]ead to a layer thickness smaller than that which can be obtained with the amount of oxygen according to the invention, and to a coefficient of friction de~initely higher than 0.07; an amount of oxygen per unit area of part to be treated lower than 10 3 mg/cm2 would result in a layer, the thickness of which would be too small to rub correctly.
.
A second example is given for a part treated at a temperature of 700C. The line 27, which corresponds to said treating temperature and is plotted at the ordinate 700C on I~ the diagram of Fig. 3, passes through the hatched area 3 accord-¦~ ing to a period of treating time ranging from 15 minutes to 5 ~-hours. The part will thus be treated within said period of ~;~ time to obtain the qualities defined hereinabove, with an ~
i amount of oxygen still ranging from 10 3 to 2.55 mg/cm2. ~ -,. .... .
~ -, ~ - 13 -:
,. , ~ ., :,
Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for treating a mechanical part, an outer surface of which contains titanium for improving the frictional properties and the resistance of such parts to wear-ing and seizing which method comprises at least partially removing a natural laycr of oxide which initially covers said outer surface which contains titanium, heating the part in an enclosure inside which a vacuum is created by a vacuum system over a limited period of time, isolating the enclosure containing the part from the vacuum system, introducing into said enclosure an amount of oxygen strictly defined as a function of the outer surface of the part and heating said part in said enclosure to a temperature in the range from 450°C to 880°C, the pressure in the enclosure, before the introduction of oxygen, ranging from 1 to 10-8 Torr, and the amount of oxygen inside the enclosure is defined according to an increasing function of the total outer surface of the part to be treated, said amount of oxygen ranging from 10-3 to 2.55 mg/cm2.
2. A method according to Claim 1, comprising the following steps in succession: (a) at least partially removing a part of the natural layer covering the part, (b) disposing the part of an enclosure, (c) creating a vacuum in said enclosure by means of a vacuum system for a limited period of time, (d) isolating the enclosure from the vacuum system, (e) introducing said amount of oxygen into the enclosure, and (f) heating the enclosure to a temperature ranging from 450°C
to 880°C.
to 880°C.
3. A method according to Claim 1, which comprises the following sequence of the operations: (a) removing a part of the natural layer of oxide, (b)disposing the part inside the enclosure, (c) heating the enclosure to a temperature higher than the ambient temperature, (d) creating a vacuum for a limited period of time in the enclosure, (e) introducing the oxygen, and (f) heating the enclosure to the temperature of treatment.
4. A method according to Claim 1, in which the total current of oxygen required for the treatment is introduced at the start of the treatment.
5. A method according to Claim 1, in which the oxygen required for the treatment is introduced throughout the heating step.
6. A method according to Claim 1, in which the amount of oxygen required for the treatment is introduced in gaseous form.
7. A method according to Claim 1, in which the oxygen required for the treatment provided in the treatment enclosure forms a substance capable of releasing oxygen at the treatment temperature.
8. A method according to Claim 1, in which the oxygen required for the treatment is provided by degassing a body which has previously absorbed oxygen.
9. A method according to Claim 1, in which the accurate amount of oxygen as a function of the area of the parts to be treated is accompanied by a filler gas which is a rare gas contained in air.
10. A method according to Claim 1, in which, during the treatment, the amount of oxygen per unit area temporarily has a value ranging from 0.11 to 2.55 mg/cm2.
11. A method according to Claim 1, in which the minimum thickness to be removed from the natural layer of oxide initially covering the part is at least 2 microns.
12. A method according to Claim 1, in which the temperature and the time of treatment of the part are determined from a diagram illustrated by Figure 3 of the accompanying draw-ings, so as to correspond to a point lying inside a hatched area included between the two limiting curves.
13. A method according to Claim 1, in which the temp-erature of treatment ranges from 500°C to 750°C.
14. A method according to Claim 1, in which the time during which the temperature is maintained ranges from 2 to 30 hours.
15. A method according to Claim 1, in which cooling of the parts takes place slowly inside the enclosure by stopping heating of the enclosure.
16. A method according to Claim 1, in which cooling of the parts after the treatment is carried out rapidly either inside or outside the enclosure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7329270A FR2240302A1 (en) | 1973-08-06 | 1973-08-06 | Improving wear resistance of titanium contg. articles - in industrial low temp. process by removing surface oxide heating in vacuum chamber and then admitting oxygen |
| FR7340795A FR2250831A1 (en) | 1973-11-09 | 1973-11-09 | Improving wear resistance of titanium contg. articles - in industrial low temp. process by removing surface oxide heating in vacuum chamber and then admitting oxygen |
| FR7423069A FR2276396A2 (en) | 1974-06-27 | 1974-06-27 | Improving wear resistance of titanium contg. articles - in industrial low temp. process by removing surface oxide heating in vacuum chamber and then admitting oxygen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049905A true CA1049905A (en) | 1979-03-06 |
Family
ID=27250166
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA206,318A Expired CA1049905A (en) | 1973-08-06 | 1974-08-06 | Method for treating parts made of titanium or titanium alloy; and parts produced thereby |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS581187B2 (en) |
| CA (1) | CA1049905A (en) |
| DE (1) | DE2437876A1 (en) |
| GB (1) | GB1477370A (en) |
| IT (1) | IT1017896B (en) |
| NL (1) | NL7410549A (en) |
| SE (1) | SE401692B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5312737A (en) * | 1976-07-22 | 1978-02-04 | Tokyo Shibaura Electric Co | Treatment for inhibiting hydrogen absorption of titanium |
| DE3104112C2 (en) * | 1981-02-06 | 1984-12-13 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Process for the production of oxide layers |
| DE3215314C2 (en) * | 1982-04-23 | 1984-12-06 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Process for the production of oxide layers on a titanium-based alloy surface |
| DE3145236C2 (en) * | 1981-11-13 | 1984-11-22 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Process for the production of deformation-resistant oxidic protective layers |
| DE3338852A1 (en) * | 1982-12-11 | 1984-06-14 | Maschf Augsburg Nuernberg Ag | METHOD AND DEVICE FOR COATING WORKPIECES BY MEANS OF CHEMICAL, HETEROGENIC GAS PHASE REACTION |
| DE3419638A1 (en) * | 1984-05-25 | 1985-11-28 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | METHOD FOR PRODUCING OXIDIC PROTECTIVE LAYERS ON THE SURFACE OF METALS OR. METAL ALLOYS |
| JPH0310060A (en) * | 1989-03-23 | 1991-01-17 | Mitsubishi Motors Corp | Surface treatment for titanium or titanium alloy |
| DE102014205413A1 (en) * | 2014-03-24 | 2015-09-24 | Siemens Aktiengesellschaft | Coating process and component |
| CN113134709B (en) * | 2021-03-26 | 2023-08-22 | 中科听海(苏州)电子科技有限责任公司 | Preparation method of super-hydrophobic gradient coating for corrosion prevention of submarine sonar shell |
| CN114088870A (en) * | 2021-11-26 | 2022-02-25 | 中国航发北京航空材料研究院 | Test method for titanium fire spreading characteristic of aircraft engine blade |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3408236A (en) * | 1964-07-16 | 1968-10-29 | Hoover Ball & Bearing Co | Wear-resistant titanium alloy and method of producing same |
| US3472704A (en) * | 1966-09-21 | 1969-10-14 | Ca Atomic Energy Ltd | Wear resistant member |
-
1974
- 1974-08-02 IT IT25968/74A patent/IT1017896B/en active
- 1974-08-05 SE SE7410060A patent/SE401692B/en unknown
- 1974-08-06 CA CA206,318A patent/CA1049905A/en not_active Expired
- 1974-08-06 DE DE2437876A patent/DE2437876A1/en not_active Ceased
- 1974-08-06 GB GB3453274A patent/GB1477370A/en not_active Expired
- 1974-08-06 JP JP49090671A patent/JPS581187B2/en not_active Expired
- 1974-08-06 NL NL7410549A patent/NL7410549A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5053246A (en) | 1975-05-12 |
| JPS581187B2 (en) | 1983-01-10 |
| GB1477370A (en) | 1977-06-22 |
| DE2437876A1 (en) | 1975-02-20 |
| IT1017896B (en) | 1977-08-10 |
| NL7410549A (en) | 1975-02-10 |
| SE7410060L (en) | 1975-02-07 |
| SE401692B (en) | 1978-05-22 |
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