CA2102222C

CA2102222C - Improvements in or relating to razor blades

Info

Publication number: CA2102222C
Application number: CA002102222A
Authority: CA
Inventors: Manohar S. Grewel; Chong-Ping P. Chou; Steve S. Hahn; John Madeira
Original assignee: Gillette Co LLC
Current assignee: Gillette Co LLC
Priority date: 1991-04-26
Filing date: 1992-04-22
Publication date: 1998-08-25
Anticipated expiration: 2012-04-22
Also published as: EP0582676A4; ES2143473T3; MX9201910A; EP0582676A1; EG19582A; AU2184292A; ATE190892T1; JPH06507100A; AU666659B2; TR26981A; WO1992019425A3; KR100241239B1; HUT69255A; CN1068058A; CA2102222A1; DE69230822T2; TW221976B; RU2108234C1; DE69230822D1; WO1992019425A2

Abstract

A razor blade includes a substrate with a wedge-shaped edge, an interlayer of material selected from the group consisting of nickel, niobium, silicon, silicon carbide, tantalum, vanadium and alloys of such materials on the tip and flanks of the wedge-shaped edge, the thickness of the interlayer preferably being in the range of about 50-500 angstroms and a layer of diamond or diamond-like carbon material on the interlayer that preferably has a thickness of about two thousand angstroms and that defines a tip radius of less than about 1000 argstroms.

Description

wo 92/1942~ Pcr/us92/0333~

2 1 ~) 2 ~J 2 ;;;~ "

T~ Ko~ TS T~ OR ~2~TIN~ TO R~ZOR BI~ADES
This invention relates to improved razors and -~
razor blades and to pLG~ c for ~ cing razor blades or similar cutting tools with sharp and durable :~
cutting edges- !
A razor blade typically is ~ormed o~ suitable sub~trate material such ~s a~tal or c~ramic and an edge is formed with u~e-~hape configuration with-an ultimate ed~e or tip that has a radius of le~s than about l,000 a.. ~ ms, the wedge shaped ~urfaces having an inc~uded angl~ of 1~8s than 30-. ~s shaving action is severe and blade ~dge da~age frequently r~sults and to ~r~h~n~e s~avability, th~ use of one or more layers of suppl~ntal coating ~ateri~Ll has been ~C~ for ~ha~re ~acilitation, and~or to increase the hardness and/or corrQsion r~sis~anc~ of the shaving edge. A
nu~b~r o~ ~uch ~-oating material~ have been propo~ed, s~ch as~ po~ eric ~aterials and ~etals, a~ well as oth~r materials including diamond and diamond-like carbon (D~C) ~aterial. Each such lay~r or layer~ o~
suppl~mental material must have adhesion compatibility so that ea~h l~yer rQ~ain~ ~irmly adhered to the substrate th~ o~ the us~ul life of the razor blade, and desirably prQ~ide ch~racteri~tics ~uch as : 25 im~ 3 ~hav~bility, imp~&~ haL 1~ S ~nd/or corrosion resistance while not ~dversely affecting the geometry and cut~ing ef~ectiveness o~ the shaving edge .
.~

WO92/19425 PCT/US9~/03330 ~ 2~?'~ - 2 -It has been proposed to provide the cutting edges of razor blades with improved mechanical properties by applying to the sharpened edge of the substrate a coating of diamond or diamond-like carbon (DLC) material. Such materials may be characterized as having substantial sp3 carbon bon~in~; a mass density greater than 1.5 grams/cm3; and a Raman peak at about 1331 cm-1 (diamond) or about 1552 cm~l (DLC). However, such p,,~ have not been satisfactory due to the ten~ency of the diamond or diamond-like coating to have ~; . poor ~h~sion to and to peel off from the wed~e-shaped ;. edge o~ the substrate. It has been found that an interlayer of molybdenum provides e~cellent adhesion of the diamond or diamond-like carbon to the ~e~e-shaped edge of the substrate, but it has been found that under certain Arcelerated corrosion testing conA~tions such as i~mer~ion in hot distilled water at 80-C. for 16 hours, a diamond-like cArhon coating can delaminate from a molyh~en~m interlayer and the steel blade substrate by what appears to be an ele_~ochemical reaction~
In accor~An~e with one a~pect of ~he invention, there i~ provided a razor blade co~prising a sub~trate wi~h a wedge-shaped edge, an interlayer of m~terial ~elected from the ~Lo~y consisting of - ~olybdenum, nickel, niobiu~, silicon, ~ilicon carbide, tantalum, v~n-~um, and all~y~ of ~uch materials on the tip and flank~ of the WQd~a -h~pQd ~dg~, th~ thiokness of the interlayer preferably being in th~ range of about 50-500 a.. y~L~oms, and a layer of diamond or diamond-l~ke carbon material on the interlayer that preferably has a thicknes~ of at least ~bout 1200 a..~ oms, defines a tip radius of le8s than about 400 a,.~L oms and an aspect ratio in the range of 1:1-3:1.
The blade ~Yh~hit~ excellent shaving properties and W0 92/1942~ PCr~US92/0333() ~''.
'' long shaving li.fe.
In particular embodiments, the razor blade ~:
substrate is steel; the diamond or DLC coating is at least twice as hard as the metal substrate; the wedge-shaped edge is formed by a sequence of mc~-h~ni cal abrading steps; and the layers of interlayer material (a preferred materi~l being niobium) and diamond or diamond-like carbon material are formed by sputtering material from targets of the interlayer material and ~
graphite. ~:
- In accor~nce with another aspect of the :
invention, there is provided a process for forming a razor blade that includes the steps of providing a substrate, forming on an edge of the substrate a wedge-~ped sharpened edge that has an included angle of less than 30- and a tip radius (i.e. th~ estimated radius of the larger circle that may be positioned ~.
within the ultimate tip of the edge when such ultimate tip is viewed under a -c~n~ ela_~L~n mio ~oope at magni~cations of at ~east 25,000) preferably of less than 1,200 a"y~r oms; ~er~iting a lay~r of interlayer material selected from the group consisting of molyh~enl~m, nick~l, niobium, ~ilicon, 8~ licon carbide, tantalum, v~n~um, and alloy~ of such materials on the ~harpened edqe; and ~ep~iting a lay~r of diamond or di~mond-lik~ materi~l on th~ int~rlayer to provide a radi~s at the ultimate tip o~ the dlamond or diamond-like c~r~on ~ater~al of less than about 1,000 angstroms.
The interlayer and the diamond ox DLC layer may be AeroRit~d by Yarious te~nlque~ ~uch as plasma decompostt~ion Or l.y~Loc-r~n ga~es, sputter ~ep~Qition u~lng ions ~ro~ ~ither a plas~ or an ion gun to b~mbard a target, directly us~ng a beam of carbon ions, and ion beam assisted ~pQsition ~IBAD) process using WO92/1942~ PCTtUS92/03330 '?'~

either E-Beam or sputtering sources.
In a particular process, the substrate is mechanically abraded in a sequence of ~oning steps to form the sharpene~ edge; layers of niobiu~ and diamond or diamond-like carbon material are successively deposited by sputtering; t~e niobium interlayer having a thickness of less than about five hundred angstroms, and the diamond or DLC coating on the niobiu~ coated cutting edge having a thickness of at least about lo twelve h~-~cl angstroms: the layer of diamond having a ' Raman peak at about 1331 cm~1~and:the layer of diamond-like carbon (DLC) material having a Raman peak at about 1550 cm~l; substantial sp3 carbon bonding; and a mass density~qreater than 1.5 grams/cm3; and an adherent polymer coating is applied on the diamond or DLC coated cutting edge:~
In accor~nco w~th another aspect of the invention, there is provided~a shaving unit that comprises blade 4~ ,0rt s~ru~ e that has external surfaces for engaging user s~in~ and rearwardly of the blade edqe or edges and at least one blade member secured to the ~ o~ structure. The razor blade stru~L~e secured to the ~upport structure includes a ~ub~trate with a wedge-~h~pe~ cutting edg~ de~ined by ~acot3 th~t haY~ an included an~Ie of 1~8 than so~ Qn de ~ ae~ at a distance Or for~y micrometers from the ~harpened tip, an:interlayer selected from the yLvu~ consisting of molybdenum, nickel, niobiu~, silicon, silicon carbide, tantalum, vAnA~ium, and alloy of such materials and a layer of ~treng~benlng material:on the interlay~r that ha- a thickne~s of at least twelve~ d :angstsoms fro~ the shaspened tip : of~a1d~;sub-trat ~to a d1stance of forty ~icrometers from the sharpened tip, and an ultimate tip d~fined by faoéts:that have lengths of at least about 0.1 ,, ~

W0~2/194~ PCT/US92/03330 ~i ' 2 ~ 2 .

micrometer and define an included angle of at least sixty degrees, a radius at the ultimate tip of the strengthening material of les~ than 400 angstroms and an aspect ratio in the range of 1:1-3:1.
In a par~icular shaving unit, the razor blade structure includes two steel sub trates, the wedge-shaped edges are dicposed parallel to one another bQtwee~ the skin-engaging surfaces; a niobium inte~layer is between the gteel substrate and the ~dge strengthening layer and the edge strengthening layer is - of diamond or DLC m~terial; each niobium layer has a thickness of less than about f ive hundred ang~;troms;
each diamond or DLC coating has a thickness o~e about two thou~n~ ang~troms (typically ~ ra~ge of 1800-~200 a~.y~ ms dep~n~in~ on pL~ sing paramet~rs) and is characteriz~d by 8ub tant~al sp3 carbon bon~n~; a mass density gr~at~r than 1.5 gra~s/c~3; and ~ Raman peak at about 1331 cm 1 (diamond) or about 1550 cm 1 (D~C); and an adherent polymer coating is on each layer of diamond or diamond-like carbon material.
The ~h~ving unit may be ~f th~ disposable cartridga type adapted ~or coupling to and uncoupling from a r~zor hAn~l~ or may be int~gral with a h~n~le so ~hat the co~plete razor is discarded as a unit when the blade or blades becoDIe dull. The ~ront and rear skin ging gurfac:~s co4~6~rate with th.e blade edge (or edge3) to dQfine th~ shaving geo~etry. Particularly preferred shaving units are of ~e types shown in U . S .
Patent 3, 876, 563 and in U. S . Patent 4, 586, 255 .
Oth~r featur~s and ~d~ ntag~s o the inven~ion will be seen as t~ following desc:ription of particular embodi~nt5 pIC~if-O~, in con~unctio~ with the drawing3, in which:
Fig. 1 is a perspectiv~ view of a shavinq 3 5 unit in accor~nce with the invention;

W092/1942~ PCT/US92/03330 Fig. 2 is a perspective view of another shaving unit in accordance with the invention; :~
Fig. 3 is a di~grammatic view illustrating one example of razor blade edge geometry in accordance with the invention; :
Fi~. 4 is a diagrammatic view of apparatus for the practice of the invention; and Figs. 5 and 6 are Raman spectra of DLC
material deposited with the apparatus of Fig. 4.
Des~ri~tion of Parti~ular Embodiments - With-reference to Fig. 1, shaving unit 10 ;
includes structure for at~achment to a razor handle, and a platform member 12 molded of high-impact.
poly~.ene that includes struatur~ defining forward, transversely-exten~lng sk~n engaging surfac~ 14. .;
Mounted on platform member 12 are le~n~ blade 16 having sharp~ne~ edge 18 and following blade 20 having sharp~e~ edge 22. Cap memb~r 24 of molded high-impact polystyrene has stru~ture~defining skin-engaging surface 26 that is di~os~d rearwardly of blade ed~e 22, and ~fix~d to cap ~ember 24 is shaving aid composite 28.
The shaving unit ~O shown in Fig. 2 is o~ the type shown ~n Jacobso~ U.S. Patent 4,586,255 and includ@s molded body 32 with ~ront portion 34 and rear portion 36~ Resili~ntly ~ecured in body 32 are guard m ~ er 38, l~ g blad~ unit 40 and trailing blade unit 42. ~ach blade unit 40, 42 includ~s a blade member 44 that has a sharpened edge 46. A shaving aid co~pos~te 4~ i~ fricticnally 3~ured in a rece~s in rear portion 36.
A diagram~atic v~ew of the edge region of the blades 16, 20 ~nd 44 is ~hown in Fig. 3. The blade includes stainless steel body portion 50 with a wedge-shaped sharpened edge formed in a sequence of edge W092/1942~ PCT/US92/03330 3 w ~ ,~ . ~

forming honing operations that forms a tip portion 52 that has a radius typically less than 500 angstroms with facets 54 and 56 that diverge at an angle of about 13~. Deposi~ed on tip 52 and facets 54, 56 is interlayer 58 of niobium that has a thickn~ss of about 300 angstroms. Deposited on niobium interlayer 58 is outer layer 60 of diamond-like carbon (DLC) that has a thickness of about 2,000 angstroms, with facets 62, 64 that have lengths of about one-quarter micrometer each and define an included angle of about 80~, facets 62, 64 merging with main facet surfaces 66, 68 that are di~o~~1 at an included angle of abou~ 13- and an aspect ratio (the ratio of the di~tance (a) ~rom DLC
tip 70 to stainless steel tip 52 and the width (b) of the DLC coating 60 at tip 52 ) of about l.7. Deposited on layer 60 i8 an adherent telomer layer 72 that has a substantial as ~ep~sit~d thi~.~~~C but i~ r~duced to monolayer thickness during initi~l shaving.
Ar~r~tUs for p~o~ ng blades o~ the type shown in Fig~ 3 ~ diagra~atically illustratQd in Fig.

4. That appar~tus ~nclude~ a DC planar ~agnetron sputtering sy~t~ manufa~u~e~ by Vac Tec Systems of Boulder, Colorado th~t has stain~ess steel chamber 74 with wall ~tructure 80, door 82 and ba~e structure B4 in which i~ formed port 86 coupled to a 3uitabl~ vacuum ~y~te~ ~not ~hown~ ed in chamber 74 is carousel ~u~ 88 with upst~n~n~ ort mQmbQr 90 on which i~ dl~ e1 ~ ~t~ck of r~zor blades 92 w~th their sharp~n~ edge~ 94 in alignment and ~acing outwardly 0 from a~ort 90. Also di~ in cha~ber 74 are rt structure 76 ~or target member 96 of niobium (gg.99% pure) and ~u~ort structure 78 for target member g8 o~ graphite (99.999% pure~. Targets 96 and 98 are vertically di~ e~ plates, each about twelve centimeters wide and about thirty-seven cQntimeters w092/19~2~ PCTtUS92/03330 .,?,~?,'2i'' long. Support structures 76, 78 and 88 are electrically isolated from chamber 74 and electrical connections are provided to connect blade stack 92 to :
RF power supply 100 through switch ~02 and to DC power :
supply 104 through switch 106; and targets 96 and 98 are connected through switches 108, 110l respecti~ely;
to DC magnetron power supply 112. Shutter structures 114 and 116 are disposed adjacent targets 96, 98, respectively~ for movement between an open position and a position oh~ ring its ad~acent targetO
- Carousel 88 supports the blade 6tack 92 with the blade edges 94 spaced about seven centi~eters from the op~o~ target plate 96, 98 and is rotatable about a vertical axis between a first position in which blade .
stack 92 is in o~_r~ al~nment w~th niobium target 96 (Fig. 4~ and a second position in which blad~ stack 92 is in o~l,o~~d alignment w~h graphite target 98.
In a particular p~ocF-_sing sequQnce t a stack of blades 92 (five centimet~rs high) is secured on ~ rt 90; chamb~r 74 i~ evacuated; the targets 96, 98 are cl~ by DC sputtering ~or five minute~; switch 102 is then clo~ed and the blade~ 92 are RF cleaned in an argon envirs~ment for five minut~s at a pressure of ten ~illitorr, an argon flow of 200 sccm and a power of 1.5 kilowatt~; the argon flow is then reduced to 150 ~co~ at a pre~ure o~ 2.0 millitorr in chamber 74;
swi~ch 106 is clo~Qd to apply a DC bi~s o~ -~5 volts on blades 92; switch 108 i3 clo~d to comm2nce sputtering at one kilowatt power and shutt~r 114 in front of niobium targ~t 96 is opened for thirty s~cond~ to deposit a nio~ium layer 58 o~ zlbout 300 al.yaL~oms thickr~eQ~ on the bl~de edges 94. Shutter 114 is then closed, switches 106 and 108 are Q]?9nf ~ ~ and carousel 88 is ~otated 90- to j~ct~ro~e the blade edges of blade stack 92 with graphite target 98. Pressure in chamber wo 92tl942~ PCI/US92/03330 ~ ~ D 2 ~

74 is maintained at two millitorr with an argon flow of 150 sccm; switch 110 is closed to sputter graphite target 98 at 750 watts; switch 102 is closed to apply a 13~56 MHz RF bias of eight hundred watts (-420 volts DC
self bias voltage) on blades 92, and concurrently shutter 116 is opened for twenty minutes to deposit a DLC layer 60 of about two thousand angstro~s thickness on niobium layer 58. The DLC coating 60 had a radius at tip 70 of about 350 ~ ms that is defined by facets 62, 64 that have an included angl of about 80-, and an a~pect ratio of about 1.9:$. A6 illustrated in Fig. 5, Raman spe~.o~copy of the coating mat~rial 60 deposited in this process shows a broad Raman peak 118 exten~in~ between about 1350 and 1530 cm-l wave numbers, a ~p~ctrum typical of DLC stru~l uL~.
A coating 72 of polytetrafluoroethylene telomer is th~n ~pplied to the DLC-coated edges of the blades. ThQ y~'OC E Q~ involvss h~tin~ th2 bl ~$ i~ a neutral atmo~r~er~ of argon and pro~iding on the cutting ~ of the blades an adherent and friction-reducin~ polymer coating of ~olid PTF~. Coatings 58 and 60 were ~ir~ly adherent to the blade body 50, provided low wet wool felt cutter ~orce (the lowest of the fir~t ~ive cuts with wet wool ~elt (L5) being about 0.4~ kilogram), and withstood r~peated applications of wool falt ~utter force~ i~dicating ~h~t the DLC coating 60 is substantially unaf~ected by e~ ure t~ the severe conditions of ~his felt cutter test and remains firmly adherQd to the blade body 50, even after immersion in 80-C. distilled wat~r for sixt~n hours.
Resulting blade elements 44 w~re assembled in cartridge units 30 o~ th~ typ~ shown in Fig. 2 and ~haved with ~c~llent shaving results.
In another exa~pl~, target 96 i~ ~olybdenum 3S and target g8 is graphite. In a particular processing WO92/1942' PCT/US92/0333( ?~qJ~

sequence with that system, chamber 74 is evacuated; the targets 96, 98 are cleaned by DC sputtering for five minutes; the blades 92 are then RF cleane~ in an argon environment at a pressure of ten millitorr at a power of 1.5 kilowatts and an argon flow of 200 sccm; the argon flow reduced to 150 8CCm at a pre~sure of two millitorr in chamber 74; shutter 114 in front of molybdenum target 96 is opened, and target 96 is sputtered at one kilowatt power with a bias of -150 volts on bl~ 82 for twenty-two seconds to deposit a molybdenum layer 58 of about 200 angstroms thi.ckness on the blade ~dges 94. Shutter 114 i8 then clos~d, and :-carousel 88 is rotated ~0- to juxtapo~e blade stack 92 with graphite target 98. Pressure in chamber 74 is main~1r~ at two millitorr with an argon fl~w of 150 sccm, shutter 11~ i~ op~n~, and graphite target 9~ is sputtered at 900 wat~s with a bias of -150 volts on blades 92 for 10 minut~s to ~posit a DLC layer 60 of about 800 angstroms ~hi~n~s on molybdenum layer 58.
A~ illu~tr~t~d in Fig. 6, Ra~n ~pect .-~opy of th~
coating ~t~rial 60 ~ero~t~d in thi~ p~o~c shows a ~road Raman peak 120 centered at about 1525 em-l wave nu~ber, a ~pectru~ typical of DLC structure. The DLC
co~ting 60 wa~ firmly adherent to the ~lade body 50 and wi~h tood repeated applications of wool felt cutter ~o~c~s, indicating that the DLC coating 60 is sub~tan~ially unaff~cted by e~o~ure to the severe conA~tion~ o~ this ~elt cutter test and rQmains firmly adhered to ~he blade body 50. Its tip 70 had a radius of about 700 a-ly~oms and an aspect ratio o~ 1.7:1. ;
A coating 72 of polytetrafluoroet~ylene telomer wa~ then applied to the VLC-coatad ~ s of the blades in a~L ~ with the ~e~h~n~ of U~S. Patent No. 3,518,110. This p~oc~ss involves heating the 3~ blades in a neutra~ atmosphere such as nitrogen or WO92/19~2~ PC~'/US92/03330 argon or a reducing atmosphere such as cracked ammonia and providing on the cutting edges of the blades an adherent and friction-reducing polymer coating of solid PTFE. The resulting blade elements 44 were assembled S in cartridge units 30 of the typ~ shown in Fig. 2 and shaved with ~c~llent shaving r~sult~. :
In another proces5ing ~equence, chamber 74 --was evacuated; the targets 96, 98 w~re cleaned by DC
sputtering for five minutes; the blades %2 wer~ then RF
cleA~Q~ in an argon enYironment at a pressure of ten millitorr at a power of 1.5 kilowatts and an argon flow of 200 sccm ~or two minutes; the argon flow re,duced to 150 sccm a~ a pressure of two millitorr in chamber 74;
shutter 114 in front of molybdenu~ target 96 ~a~ then opened; and targQt 9o was sputtered at one kilowatt power with a bias of -150 volts on blades 92 for thirty-two ~ to deposit a molyhA~nl~m layer 58 of abo~t 300 a.~ vms thickness on the bIade edges 94.
Shutt~r 11~ was closed and carousel 88 was rotated 90~
to jux~r~s~ blade ~tack 92 with graphite target 98.
Pressure in ch~mber 74 was maintained at two millitorr with an argon ~low of 150 ~cc~, ~hutt~r ~6 was op~ned, and gr~phite target g8 ~as sputtered at 500 watts with a ~ o~ -loO volts on blad~s 92 for ten minutes to ~5 ~ero~i~ a DLC layer 60 of about 1,000 angstro~s ~hickness on ~olybdenum layer 5~. The resulting blades had firmly a~herent DLC coatings 60 and were shaYed with excellent shaving results~
In anothsr processing se~uence, chamber 74 was ~vacuatQd; targets 96, 98 w~r~ clsa~eA by DC
~L~ering for five ~inutes; bl~d~s 92 w~re then R~
cle~n~A in an argon en~ironm~nt at a ~ ur~ of ten millitorr ~t a power of l.5 kilowatts and an argon flow of 200 sccm for two minutes; the argon flow reduced to 150 Sccm at a pressure of two ~illitorr in chamber 74;

WO 92tl94~' PCl/US92/03330 ';?

shutter 114 in front of molybdenum target 96 was then opened; and target 96 was sputtered to deposit a ..
molybdenum layer 58 of about 200 angstroms thickness on the blade edges 94. Shutter 114 was closed and ..
carousel 88 was rotated 90 to juxtapose blade stack 92 with graphite target 98. Pressure in chamber 74 was maintained at two millitorr with an argon flow of 150 sccm, shutter 116 was o~ene~, and graphite target 9 was sputtered at 600 watts to deposit a DLC layer 60 o~
about 300 a~-y~ ms thic~e~s on ~olybdenum layer 58.
- The DLC coatings 60 were firmly adherent on resulting blades, and the DLC tips 70 had a radius o~ about 500 angstroms. -.
While particular embodiments of the invention have been shown and described, various modifications will be apparent to th08~ skill~d in the art, and :~
there~ore, it i~ not int~n~e~ that the invention be limited to the disclosed e~bodiments, or to details th~reof, ~nd departures ~ay be made therefrom within the spirit and scop~ of ~he in~ention~

Claims

1. A process for forming a razor blade comprising the steps of:
providing a substrate, forming a wedge-shaped sharpened edge on said substrate that has an included angle of less than thirty degrees and a tip radius of less than twelve hundred angstroms;
depositing a layer of molybdenum on said sharpened edge;
depositing a layer of diamond or diamond-like carbon material on said molybdenum layer; and applying an adherent polymer coating on said diamond or DLC coated cutting edge.

2. The process of claim 1 wherein said substrate is mechanically abraded in a sequence of grinding, rough-honing and finish-honing steps to form said sharpened edge.

3. The process of claim 2 wherein said finish-honing step forms facets that have an included angle of less than thirty degrees.

4. The process of claim 1 wherein said molybdenum layer on said cutting edge has a thickness of less than about five hundred angstroms, and said diamond or DLC
coating on said molybdenum coated cutting edge has a thickness of less than about fifteen hundred angstroms.

5. The process of claim 1 wherein said step of forming said wedge-shaped edge includes a finish-honing step that forms a sharpened edge with an ultimate tip radius of less than about twelve hundred angstroms.

6. The process of claim 1 wherein said layer of diamond or DLC carbon material is deposited by a technique selected from the group consisting of plasma decomposition of hydrocarbon gases, sputter deposition using ions from either a plasma or an ion gun to bombard a graphite target, directly using a beam of carbon ions, and an ion beam assisted deposition (IBAD) process using either E-Beam or sputtering sources.

7. A process for forming a razor blade comprising the steps of providing a substrate, forming on said substrate a wedge-shaped edge that has an included angle of less than 30° and a tip radius less than 1,200 angstroms; depositing a layer of molybdenum on said wedge-shaped edge; depositing a layer of diamond or diamond-like material on said molybdenum layer to provide a radius at the ultimate tip of said diamond or diamond-like material of less than 1,200 angstroms; and applying and adherentpolymer coating on said diamond or DLC coated cutting edge.

8. The process of claim 7 wherein said layers of molybdenum and diamond or diamond-like material are deposited by sputtering.

9. The process of claim 7 wherein said molybdenum layer on said wedge-shaped edge has a thickness of less than about five hundred angstroms, and said diamond or DLC coating on said molybdenum coated cutting edge has a thickness of less than about fifteen hundred angstroms.

10. A razor blade comprising a substrate with a wedge-shaped edge defined by facets that have a width of at least about 0.1 millimetre and an included angle of less than thirty degrees, a layer of molybdenum on said wedge-shaped edge; a layer of diamond or diamond-like carbon material on said molybdenum layer; and applying an adherent polymer coating on said diamond or DLC coated cutting edge.

11. The razor blade of claim 10 wherein said layer of diamond or diamond-like carbon (DLC) material has a Raman peak at about 1331 cm-1 (diamond) or about 1552 cm-1 (DLC).

12. The razor blade of claim 11 wherein said layer of diamond or diamond-like carbon (DLC) has an aspect ratio of less than about 3:1; substantial sp3 carbon bonding;
and a mass density greater than 1.5 grams/cm3.

13. The razor blade of claim 11 wherein said molybdenum layer has a thickness of less than about five hundred angstroms, and said diamond or DLC coating on said molybdenum layer has a thickness of less than about fifteen hundred angstroms.

14. A razor blade comprising a substrate with a wedge-shaped edge, a layer of molybdenum on the tip and flanks of said wedge-shaped edge, the thickness of said molybdenum layer being in the range of about 50-500 angstroms, and a layer of diamond or diamond-like carbon material on said molybdenum layer, said layer of diamond or diamond-like carbon material having a thickness of about 200-1,500 angstroms anddefining a tip radius of less than about 1,000 angstroms.

15. The razor blade of claim 14 wherein said substrate is steel; said wedge-shaped edge is formed by a sequence of mechanical abrading steps; and said layers of molybdenum and diamond or diamond-like carbon material are formed by sputtering.

16. The razor blade of claim 15 wherein said layer of diamond or diamond-like carbon (DLC) material has substantial sp3 carbon bonding; a mass density greater than 1.5 grams/cm3; and a Raman peak at about 1331 cm-1 (diamond) or about 1552 c-1 (DLC); and further including an adherent polymer coating on said layer of diamond or diamond-like carbon material.

17. A shaving unit comprising support structure that defines spaced skin-engaging surfaces, and razor blade structure secured to said support structure, said razor blade structure including a substrate with a wedge-shaped edge, a layer of molybdenum on said wedge-shaped edge; a layer of diamond or diamond-like carbon material on said molybdenum layer, said diamond or diamond-like carbon coated wedge-shaped edge being disposed between said skin-engaging surfaces; and an adherent polymer coating on each said layer of diamond or diamond-like carbon material.

18. The shaving unit of claim 17 wherein said razor blade structure includes two substrates, and said coated wedge-shaped edges are disposed parallel to one another between said skin-engaging surfaces.

19. The shaving unit of claim 18 wherein each said layer of diamond or diamond-like carbon material has substantial sp3 carbon bonding; a mass density greater than 1.5 grams/cm3; and a Raman peak at about 1331 cm-1 (diamond) or 1552 cm-1 (DLC);
each said molybdenum layer has a thickness of less than five hundred angstroms; and each said diamond or DLC coating on said molybdenum layer has a thickness of less than fifteen hundred angstroms.

20. A process for forming a razor blade comprising the steps of:
providing a substrate, forming a wedge-shaped sharpened edge on said substrate that has an included angle of less than thirty degrees and a tip radius of less than twelve hundred angstroms;

depositing an interlayer of material selected from the group consisting of silicon carbide, vanadium, tantalum, niobium, and niobium-molybdenum alloy and alloys of such materials on said sharpened edge; and depositing a layer of diamond or diamond-like carbon (DLC) material on said interlayer.

21. The process of claim 20 wherein said substrate is mechanically abraded in a sequence of honing steps to form said sharpened edge.

22. The process of claim 20 and further including the step of applying an adherent polymer coating on said diamond or DLC coated cutting edge.

23. The process of claim 20 wherein said interlayer on said cutting edge has a thickness of less than about five hundred angstroms, and said diamond or DLC coating on said interlayer coated cutting edge has a thickness of, at least twelve hundred angstroms from the sharpened tip of said substrate to a distance of forty micrometers from the sharpened tip.

24. The process of claim 20 wherein said substrate is of metal and said diamond or DLC coating is at least twice as hard as said metal substrate.

25. The process of claim 20 wherein said layer of diamond or DLC carbon material is deposited by a technique selected from the group consisting of plasma decomposition of hydrocarbon gases, sputter deposition using ions from either a plasma or an ion gun to bombard a graphite target, directly using a beam of carbon ions and an ion beam assisted deposition (IBAD) process using either E-Beam or sputtering sources.

26. The process of claim 20 wherein said layer of diamond or diamond-like carbon material is deposited in an argon atmosphere in an evacuated chamber in which a graphite target and a shutter are located; said graphite target is energized; and said shutter is opened to deposit said layer of diamond or diamond-like carbon material on said sharpened edge while an RF bias is applied to said substrate.

27. The process of claim 26 and further including a niobium target in said chamber, and an interlayer of niobium is deposited on said blade edge by sputtering.

28. A process for forming a razor blade comprising the steps of providing a substrate, forming on said substrate a wedge-shaped sharpened edge that has an included angle of less than 30° and a tip radius of less than 1,200 angstroms;
depositing an interlayer of material selected from the group consisting of silicon carbide, vanadium, tantalum, niobium, and niobium-molybdenum alloy and alloys of such materials on said wedge-shaped edge; and depositing a layer of diamond or diamond-like carbon (DLC) material on said interlayer to provide a radius at the ultimate tip of said diamond or diamond-like carbon material of less than 1,200 angstroms.

29. The process of claim 28 wherein said interlayer and said diamond or diamond-like carbon material are deposited by sputtering.

30. The process of claim 28 wherein said interlayer on said wedge-shaped edge has a thickness of less than about five hundred angstroms, and said diamond or DLC coating on said interlayer cutting edge has a thickness of at least about twelve hundred angstroms.

31. The process of claim 30 and further including the step of applying an adherent polymer coating on said diamond or DLC coated cutting edge.

32. The process of claim 31 wherein said diamond or DLC
coating on said cutting edge has a thickness of about two thousand angstroms.

33. A razor blade comprising a substrate with a wedge-shaped edge defined by facets that have a width of at least about 0.1 millimetre and an included angle of less than thirty degrees, an interlayer of material selected from the group consisting of silicon carbide, vanadium, tantalum, niobium, and niobium-molybdenum alloy and alloys of such materials on said wedge-shaped edge; and a layer of diamond or diamond-like carbon material on said interlayer.

34. The razor blade of claim 33 wherein said layer of diamond or diamond-like carbon (DLC) material has a Raman peak at about 1331 cm 1 (diamond) or about 1552 cm 1 (DLC).

35. The razor blade of claim 34 wherein said layer of diamond or diamond-like carbon (DLC) has an aspect ratio of less than about 3:1; substantial sp3 carbon bonding; and a mass density greater than 1. 5 grams/cm3.

36. The razor blade of claim 35 and further including an adherent polymer coating on said layer of diamond or diamond like carbon material.

37. The razor blade of claim 36 wherein said interlayer is of niobium and has a thickness of less than about five hundred angstroms, and said diamond or DLC coating on said interlayer has a thickness of about two thousand angstroms.

38. A razor blade comprising a substrate with a wedge-shaped edge, an interlayer of material selected from the group consisting of silicon carbide, vanadium, tantalum, niobium, and niobium-molybdenum alloy and alloys of such materials on the tip and flanks of said wedge-shaped edge, the thickness of said interlayer being in the range of about 50-500 angstroms, and a layer of diamond or diamond-like carbon material on said interlayer, said layer of diamond or diamond-like carbon material having a thickness of at least about twelve hundred angstroms from the sharpened tip of said substrate to a distance of forty micrometers from the sharpened tip and defining a tip radius of less than about 1000 angstroms.

39. The razor blade of claim 38 wherein said substrate is steel; said wedge-shaped edge is formed by a sequence of mechanical abrading steps; said interlayer is of niobium; and said interlayer and diamond or diamond-like carbon material are formed by sputtering.

40. The razor blade of claim 39 wherein said layer of diamond or diamond-like carbon (DLC) material has substantial sp3 carbon bonding; a mass density greater than 1.5 grams/cm3;

and a Raman peak at about 1331 cm-1 diamond or about 1552 cm-1 (DLC); and further including an adherent polymer coating on said layer of diamond or diamond-like carbon material.

41. A shaving unit comprising support structure that defines spaced skin-engaging surfaces, and razor blade structure secured to said support structure, said razor blade structure including a substrate with a wedge-shaped edge, an interlayer of material selected from the group consisting of silicon carbide, vanadium, tantalum, niobium, and niobium-molybdenum alloy and alloys of such materials on said wedge-shaped edge; and a layer of diamond or diamond-like carbon material on said interlayer, said diamond or diamond-like carbon coated wedge-shaped edge being disposed between said skin-engaging surfaces.

42. The shaving unit of claim 41 wherein said razor blade structure includes two substrates, and said coated wedge-shaped edges are disposed parallel to one another between said skin-engaging surfaces.

43. The shaving unit of claim 42 wherein each said layer of diamond or diamond-like carbon material has substantial sp3 carbon bonding; a mass density greater than 1.5 grams/cm3; and a Raman peak at about 1331 cm-1 (diamond) or 1552 cm-1 (DLC);
each said interlayer has a thickness of less than five hundred angstroms; and each said diamond or DLC coating on said interlayer has a thickness of about two thousand angstroms;
and further including an adherent polymer coating on each said layer of diamond or diamond-like carbon material.

44. The process of claim 20 wherein said interlayer material is silicon carbide.

45. The process of claim 20 wherein said interlayer material is vanadium.

46. The process of claim 20 wherein said interlayer material is tantalum.

47. The process of claim 20 wherein said interlayer material is niobium.

48. The process of claim 20 wherein said interlayer material is niobium molybdenum alloy.

49. The razor blade of claim 33 wherein said interlayer material is silicon carbide.

50. The razor blade of claim 33 wherein said interlayer material is vanadium.

51. The razor blade of claim 33 wherein said interlayer material is tantalum.

52. The razor blade of claim 33 wherein said interlayer material is niobium.

53. The razor blade of claim 33 wherein said interlayer material is niobium-molybdenum alloy.

54. The razor blade of claim 38 wherein said interlayer material is silicon carbide.

55. The razor blade of claim 38 wherein said interlayer material is vanadium.

56. The razor blade of claim 38 wherein said interlayer material is tantalum.

57. The razor blade of claim 38 wherein said interlayer material is niobium.

58. The razor blade of claim 38 wherein said interlayer material is niobium-molybdenum alloy.

59. The shaving unit of claim 41 wherein said interlayer material is silicon carbide.

60. The shaving unit of claim 41 wherein said interlayer material is vanadium.

61. The shaving unit of claim 41 wherein said interlayer material is tantalum.

62. The shaving unit of claim 41 wherein said interlayer material is niobium.

63. The shaving unit of claim 41 wherein said interlayer material is niobium-molybdenum alloy.