US3054752A - Square loop magnetic manganeseferrite material and manufacture thereof - Google Patents

Square loop magnetic manganeseferrite material and manufacture thereof Download PDF

Info

Publication number
US3054752A
US3054752A US851997A US85199759A US3054752A US 3054752 A US3054752 A US 3054752A US 851997 A US851997 A US 851997A US 85199759 A US85199759 A US 85199759A US 3054752 A US3054752 A US 3054752A
Authority
US
United States
Prior art keywords
coercivity
curve
squareness
ferrite
manganese
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.)
Expired - Lifetime
Application number
US851997A
Other languages
English (en)
Inventor
Edgar C Leaycraft
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL257266D priority Critical patent/NL257266A/xx
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to US851997A priority patent/US3054752A/en
Priority to GB35097/60A priority patent/GB887632A/en
Priority to DEJ18996A priority patent/DE1178763B/de
Priority to FR843454A priority patent/FR1279330A/fr
Application granted granted Critical
Publication of US3054752A publication Critical patent/US3054752A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C04B35/265—Compositions containing one or more ferrites of the group comprising manganese or zinc and one or more ferrites of the group comprising nickel, copper or cobalt
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C04B35/2658—Other ferrites containing manganese or zinc, e.g. Mn-Zn ferrites

Definitions

  • This invention relates to square hysteresis characteristic magnetic manganese-ferrite materials and more particularly to materials of this type employed in the manufaeture of magnetic core elements providing bi-stable binary memory elements, and to the process of manufacture thereof.
  • the bi-stable square loop magnetic core element has become a well known and valuable piece of apparatus.
  • the use and function of this element has been variously described in numerous patents, one of which is the patent to Greenhalgh 2,872,666, issued February 3, 1959.
  • cores of various coercivities can be produced by varying core compositions and sintering temperatures.
  • cores of maximum squareness can be produced from manganeseferrite systems with or Without small percentages of additives and over a range of coercivities if not only sintering temperatures but also iron oxide powder particle size, calcining temperatures and pressed densities are selected in order to produce in a finished core a sintered density of optimum value.
  • manganese-ferrite cores of various coercivities have optimum squareness when their sintered densities are approximately 4.49 to 4.53 grams per cubic centimeter, the good squareness results within the range of approximately 4.48 to 4.55. It is the object of this invention to set forth the limits of the process variables noted above within which optimum squareness and the desired sintered density are produced in manganese-ferrite core systems within a limited range of coercivities.
  • FIGURE 1 is a plot showing, for manganese-ferrite systems, values of the process variables for the production of maximum squareness cores having various sintered density.
  • FIGURE 2 is a plot, for manganese-ferrite system of FIGURE 1, of iron oxide particle size versus squareness.
  • FIGURE. 3 is a plot, for manganese-ferrite systems of FIGURE 1, of calcining temperature versus squareness.
  • FIGURE 4 is a plot, for manganese-ferrite systems of 3,054,752 Patented Sept. 18, 1962 2 FIGURE 1, of pressed density versus squareness;
  • FIGURE 5 is a plot, for manganese-ferrite systems of FIGURE 1, of sintering temperature versus squareness.
  • FIGURE 6 is a plot, for manganese-ferrite systems of FIGURE 1, of sintered density versus squareness.
  • FIGURE 7 is a showing of a hysteresis loop and indicates diagrammatically full and half select pulses for switching and resulting output voltages.
  • ferromagnetic bodies employed as magnetic memory elements are desirably possessed of a square hysteresis characteristic.
  • FIG- URE 7 there is indicated generally at 10, a hysteresis loop of such a body.
  • the loop is drawn on conventional B and H coordinates. If there is applied to the body a full select "1 driving force on the H axis as indicated by the pulse 12, the body will be driven to a H-B state or a "1 state as indicated by the point 14 on the loop, and, when the driving force is relieved, the residual magnetism in the core Br will be at a value indicated by the point 16 on the B axis.
  • the magnetic state of the body will be switched to a (--)B state or the 0 state as indicated by the point 20 on the loop, and, when the driving force is relieved, the body will retain a residual magnetism indicated by the point 22 on the B axis.
  • the ratio V V provides a highly satisfactory measure of squareness in that V is a relatively absolute value of disturbance resulting from lack of perfect squareness and V accommodates for the fact that various materials will have hysteresis loops of various B/H ratios. Thus, for a high value of B, a greater displacement between points 22 and 30 may be tolerated than for a low value of B. Accordingly, hereinafter, squareness ratio will be referred to as the expression V V and the following discussion will consider only values of V and V in the considerations of this squareness ratio.
  • compositions noted as MS, CM, NCM, and K107 are listed and it will be observed that these compositions represent manganese-ferrite systems without and with additive materials. These compositions provide cores over ranges of coercivity extending from 1.1 oersteds to 3.7 oersteds as will be hereinafter described in connection with FIG- URE 1 and having sufiiciently high degrees of squareness to permit switching as has been described in connection with FIGURE 7. Itwill be evident from the listing of the percentages of the constituents of the compositions set forth in Chart 1, that some latitude exists in the exact percentages of the constituents of the compositions.
  • the binder may be polyvinyl alcohol added in the amount of approximately 3% by Weight and the lubricant may be dibutyl p'hthalate added in the amount of approximately 4% by weight.
  • the resulting mixture is then press molded into the form of the desired body which may be of toroidal or of other desired shape.
  • the body in this condition is 70 termed a green body.
  • the green body may be heated to approximately 600 C. and the binder and lubricant which are organic compounds are driven therefrom.
  • Curve 31 shows the variation of iron oxide particle size for the production of cores of maximum squareness having various coercivities.
  • Curve 32 shows the variation of calcining temperature for the production of cores of maximum squareness over the range of coercivities.
  • Curve 33 shows the variation of green or pressed density for the production of cores of maximum squareness over the rangeof coercivities.
  • Curve 34 shows the variation of sintering temperature for the production of cores of maximum squareness over the range of coercivities.
  • Curve 35 indicates the linearcondition of sintered density for cores having maximum squareness over the range of coercivities.
  • Each of the curves of FIGURE 1 is representative of manganese-ferrite systems having ferrospinel square loop characteristics. Each of these curves represents average values of the various data points shown in the drawing for the compositions set forth in Chart 1. Data points are provided for coercivities of 1.1, 1.5, 1.8, 3.4 and 3.7. It will be evident from these curves that each of the variables follows a regular curve over the range of coercivities and that the optimum values for any desired coercivity can be predicted within reasonable limits by the contours of the curves.
  • the particle sizes indicated in FIGURE 1 within the range of approximately 0.6 to 2.0 microns is the average particle size by weight, that is, if a curve is drawn of The molded body is then placed in a furnace and the'particle, size distribution by weight percent, 50%
  • the 0.6 average particle size material has 90% of the particles by weight within the range of 0.23 micron to 3.0 microns.
  • the 0.8 average particle side has 90% of the particles by weight between 0.29 micron and 2.5 microns.
  • the 2.1 average particle size material has 90% of the particles by Weight between 0.7 micron and 8.6 microns.
  • Curve 32 of FIGURE 1 shows the calcine temperature optimum value at each of the coercivities involved.
  • calcining times may extend from approximately 30 to 180 minutes. In the examples set forth herein, calcining times were all approximately 90 minutes, this time interval is, however, relatively uncritical. It will be evident, however, that calcining temperature varies substantially linearly with coercivity rising from approximately 750 -C. for 3.7 oersted cores to approximately 950 C. for 1.1 oersted cores.
  • Curve 33 of FIGURE 1 shows optimum press densities in grams per cubic centimeter tor cores of each of the coercivities. It will be observed that this curve rises substantially linearly from approximately 2.85 grams per cc. for 1.1 coercivity cores to approximately 3.35 grams per cc. for 3.7 coercivity cores and that from the curve optimum press density of cores within the coercivity range can be predicted with reasonable accuracy. 7
  • Curve 34 of FIGURE 1 indicates the optimum sintering temperature for cores at each of the coercivities and rises from approximately 1100 C. for 3.7 coercivity .cores to approximately 1425 C. for 1.1 coercivity cores.
  • the chrome-nickel materials require slightly higher sintering temperatures and the copper materials require slightly lower sintering temperatures than those indicated by the curve, however, the unique efiects of these additives giving rise to these deviations will be understood by one skilled in the art and the deviations are relatively minor.
  • the sintering time was approximately 10 minutes.
  • Curve 35 in FIGURE 1 indicates the sintered density accompanying squareness. This density is approximately 4.51 grams per cc. It will be evident that in actual practice, minor variations on either side of this precise figure will occur, thus the range of optimum densities extends trom approximately 4.49 to 4.53. It will be noted that at the 1.5 coercivity, a sintered density of 4.55 is shown for NCM material. This results because of the fact that the iron oxide particle size employed in this material is somewhat smaller than is desirable to produce optimum conditions at 1.5 coercivity. It is believed that if the particle size and sintering temperatures for this material were to be selected as indicated by the curves 31 and 34, the sintered density for the material would fall within the optimum range. However, an outer range of densities is from 4.48 to 4.55.
  • FIGURES 2, 3, 4, 5 and 6 show the eifects on squareness, as defined by the V V ratio, of varying any one of the process variables shown in FIGURE 1 and indicate that for maximum squareness the values are substantially those indicated by the curves in FIGURE 1. Also, in each of the curves of FIGURES- 2-6, there is indicated, the value at which the sintered density is within the range 4.48 to 4.55.
  • each of the curves represents a plot of squareness as expressed by V V versus iron oxide average particle size by Weight in microns taken at data points 0.6, 0.8, and 2.0 microns as has been heretofore discussed in connection with FIGURE 1.
  • Curve 46 is drawn for NCM material at 3.7 coercivity and shows at 47 that maximum squareness is obtained with 0.6 micron particle size.
  • Curve 48 is drawn for NCM material at 3.4 coercivity and shows at 49 that maximum squareness is obtained with 0.6 micron particle size.
  • Curves 50 and 52 are drawn for NCM and CM materials, respectively, at 1.8 coercivity and show at 51 and- 53, respectively, that maximum squareness is obtained with 0.8 micron particle size.
  • Curves 54 and 56 are drawn for CM and NCM materials, respectively, at 1.5 coercivity and show at 55 and 57, respectively, that maximum squareness is obtained with 0.8 micron particle size.
  • Curves 58, 60, 62 and 64 are drawn for M8, K107, NCM and CM materials, respectively, at 1.1 coercivity and show at 59, 61, 63 and 65, respectively, that maximum squareness is obtained with 2.0 micron particle size.
  • the cores of maximum squareness have sintered densities of or most closely approaching 4.51 grams per cc.
  • each of the curves represents a plot of squareness, as expressed by V V versus calcine temperature in degrees centigrade.
  • Curve is drawn for K107 material at 3.7 coercivity and shows at '71 that maximum squareness is obtained by a calcine temperature of 750 C.
  • Curve 72 is drawn for NCM material at 3.4 coercivity and shows at 73 that maximum squareness is obtained with 75 0 C. calcine temperature.
  • Curves 74 and 76 are drawn for NCM and K107 materials-respectively, at 1.8 coercivity and show at 75 and 77 respectively, that maximum squareness is obtained with 900 C. calcine temperature.
  • Curve 78 is drawn for K107 material at 1.1 coercivity and shows at 79 that maximum squareness is obtained with 950 C. calcine temperature.
  • Curve 80 is drawn for NCM material at 1.1 coercivity and shows at 81 that maximum squareness is obtained with 900 C. calcine temperature. As has been previously discussed with respect to NCM materials, higher calcining tends to give a falling off of squareness and thus this material calcines at a slightly lower temperature than would other-wise be anticipated.
  • the cores of maximum squareness have sintered densities of or most closely approaching 4.51 grams per cc.
  • each of the curves represents a plot of squareness as expressed by V V versus pressed density in grams per cc.
  • Curves 82 and 84 are drawn for NCM and K107 materials, respectively, at 3.7 coercivity and show at 83 and 85, respectively, that maximum squareness is obtained with approximately 3.31 grams per cc. pressed density.
  • Curve 86 is drawn for NCM material at 3.4 coercivity and shows at 87 that maximum squareness is obtained with approximately 3.1 grams per cc. pressed density.
  • Curves 88, 90 and 92 are drawn for NCM, K107 and CM materials, respectively, at 1.8 coercivity and show at 89, 91 and 93, respectively, that maximum squareness is obtained with approximately 2.95 grams per cc. pressed density.
  • Curves 94 and 96 are drawn for K107 and NCM materials, respectively, at 1.1 coercivity and show at 95 and 97, respectively, that maximum squareness is obtained with approximately 2.9 and 2.8 grams per cc. pressed density respectively.
  • each of the curves represents a plot of squareness as expressed by V l V versus sintering temperature in degrees centigrade; The sintering times are approximately minutes.
  • Curves 98 and 100 are drawn for K107 and NCM materials respectively at 3.4 coercivity and show at 99 and 101, respectively, that maximum squareness is obtained with firing temperatures of approximately 1100 C.
  • Curve 102 is drawn for NCM material at 1.8 coercivity and shows at 103 that maximum squareness is obtained with a sintering temperature of 1280 C.
  • Curves 104 and 106 are drawn for NCM and CM materials, respectively, at 1.5 coercivity and show at 105 and 107, respectively, that maximum squareness is obtained with a firing temperature of 1310" C.
  • Curves 108 and 110 are drawn for K107 and NCM materials, respectively, at 1.1 coercivity and show at 109 and 111, respectively, that maximum squareness is obtained with respective firing temperatures of 1430 and 1400 C.
  • each of the curves represents a plot of squareness as express by V V versus sintered density. The squareness ratio variation was accomplished by varying pressed density. All of the other process variables were in accordance with the curves of FIGURE 1. Upon viewing the curves of FIGURE 6, it will be evident that maximum squareness occurs at approximately the value of 4.51 grams per cc. sintered density. Curves 112, and 114 are drawn for NCM and K107 materials, respectively, at 3.7 coercivity and cross the 4.51 sintered density line at points indicated at 113 and 115, respectively.
  • Curve 116 is drawn for NCM material at 3.4 coercivity and crosses the 4.51 density line at 117.
  • Curves 120 and 122 are drawn for NCM and K107 materials, respectively, at 1.8 coercivity and cross the 4.51 density line at 121 and 123, respectively.
  • Curve 124 is for CM material at 1.5 coercivity and crosses the 4.51 density line at 125.
  • Curves 128 and 129 are drawn for NCM and K107 materials, respectively, at 1.1 coercivity and cross the 4.51 density line at 130 and 131, respectively.
  • the invention involves not only the production of manganese-ferrite materials of maximum squareness within specific ranges of coercivities but also the determination of a variable, i.e., sintered density, which can be employed to indicate whether cores of maximum squareness for any given coercivity are being produced.
  • ferrite structures of the. manganese ferrite system having enhanced rectangularity of the hysteresis characteristic, said structures having a predetermined coercivity within the limits specified by the axis of abscissas of FIGURE 1, including the steps of:
  • the improvement in said process for obtaining enhanced rectangularity of the hysteresis characteristic of the ferrite structure comprising sintering said structure at a particular temperature approximately equal to the value identified by the intersection of the curve 34 of FIG. 1 with an ordinate representing the said predetermined coercivity.
  • the improvement in said process 'for obtaining enhanced rectangularity of the hysteresis characteristic of the ferrite structure comprising calcining the mixture at a particular temperature approximately equal to the value identified by the intersection of the curve 32 of FIG. 1 withan ordinate representing the said predetermined 4.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Soft Magnetic Materials (AREA)
  • Magnetic Ceramics (AREA)
  • Hard Magnetic Materials (AREA)
US851997A 1959-11-10 1959-11-10 Square loop magnetic manganeseferrite material and manufacture thereof Expired - Lifetime US3054752A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL257266D NL257266A (en:Method) 1959-11-10
US851997A US3054752A (en) 1959-11-10 1959-11-10 Square loop magnetic manganeseferrite material and manufacture thereof
GB35097/60A GB887632A (en) 1959-11-10 1960-10-13 Improvements in and relating to the manufacture of square hysteresis loop ferrite cores
DEJ18996A DE1178763B (de) 1959-11-10 1960-11-09 Verfahren zur Herstellung eines Mangan-Ferrit-kernes mit annaehernd rechteckiger Hystereseschleife
FR843454A FR1279330A (fr) 1959-11-10 1960-11-09 Ferrites magnétiques contenant du manganèse à boucle d'hystérésis rectangulaireet procédés pour leur fabrication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US851997A US3054752A (en) 1959-11-10 1959-11-10 Square loop magnetic manganeseferrite material and manufacture thereof

Publications (1)

Publication Number Publication Date
US3054752A true US3054752A (en) 1962-09-18

Family

ID=25312242

Family Applications (1)

Application Number Title Priority Date Filing Date
US851997A Expired - Lifetime US3054752A (en) 1959-11-10 1959-11-10 Square loop magnetic manganeseferrite material and manufacture thereof

Country Status (5)

Country Link
US (1) US3054752A (en:Method)
DE (1) DE1178763B (en:Method)
FR (1) FR1279330A (en:Method)
GB (1) GB887632A (en:Method)
NL (1) NL257266A (en:Method)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372123A (en) * 1962-05-25 1968-03-05 Philips Corp Method for manufacturing lithiumnickel-manganese ferrite magnetic memory cores
US4247500A (en) * 1979-12-07 1981-01-27 Bell Telephone Laboratories, Incorporated Fabrication of ferrite material
US11510684B2 (en) 2019-10-14 2022-11-29 Globus Medical, Inc. Rotary motion passive end effector for surgical robots in orthopedic surgeries
US11744648B2 (en) 2011-04-01 2023-09-05 Globus Medicall, Inc. Robotic system and method for spinal and other surgeries
US11819365B2 (en) 2012-06-21 2023-11-21 Globus Medical, Inc. System and method for measuring depth of instrumentation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3177145A (en) * 1963-02-04 1965-04-06 Ibm Manganese copper ferrite composition containing titanium and germanium and method ofpreparation

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE532384A (en:Method) * 1953-10-07 1955-04-07
FR1125577A (fr) * 1955-05-03 1956-11-02 Lignes Telegraph Telephon Matériaux ferromagnétiques à cycle d'hystérésis rectangulaire
US2818387A (en) * 1954-10-28 1957-12-31 Philips Corp Square loop ferromagnetic material
FR67809E (fr) * 1955-02-03 1958-03-24 Lignes Telegraph Telephon Matériaux ferromagnétiques à cycle d'hystérésis rectangulaire
GB797168A (en) * 1955-06-16 1958-06-25 Philips Electrical Ind Ltd Improvements in or relating to ferrite material for use at microwave frequencies andto methods of manufacturing such material
AT204795B (de) * 1955-06-30 1959-08-10 Siemens Ag Verfahren zur Herstellung magnetisierbarer Kerne
US2905641A (en) * 1953-12-22 1959-09-22 Philips Corp Method of manufacturing a magnet core having an approximately rectangular hysteresis loop

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE532384A (en:Method) * 1953-10-07 1955-04-07
US2905641A (en) * 1953-12-22 1959-09-22 Philips Corp Method of manufacturing a magnet core having an approximately rectangular hysteresis loop
US2818387A (en) * 1954-10-28 1957-12-31 Philips Corp Square loop ferromagnetic material
FR67809E (fr) * 1955-02-03 1958-03-24 Lignes Telegraph Telephon Matériaux ferromagnétiques à cycle d'hystérésis rectangulaire
FR1125577A (fr) * 1955-05-03 1956-11-02 Lignes Telegraph Telephon Matériaux ferromagnétiques à cycle d'hystérésis rectangulaire
GB797168A (en) * 1955-06-16 1958-06-25 Philips Electrical Ind Ltd Improvements in or relating to ferrite material for use at microwave frequencies andto methods of manufacturing such material
AT204795B (de) * 1955-06-30 1959-08-10 Siemens Ag Verfahren zur Herstellung magnetisierbarer Kerne

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372123A (en) * 1962-05-25 1968-03-05 Philips Corp Method for manufacturing lithiumnickel-manganese ferrite magnetic memory cores
US4247500A (en) * 1979-12-07 1981-01-27 Bell Telephone Laboratories, Incorporated Fabrication of ferrite material
US11744648B2 (en) 2011-04-01 2023-09-05 Globus Medicall, Inc. Robotic system and method for spinal and other surgeries
US11819365B2 (en) 2012-06-21 2023-11-21 Globus Medical, Inc. System and method for measuring depth of instrumentation
US11510684B2 (en) 2019-10-14 2022-11-29 Globus Medical, Inc. Rotary motion passive end effector for surgical robots in orthopedic surgeries

Also Published As

Publication number Publication date
FR1279330A (fr) 1961-12-22
GB887632A (en) 1962-01-24
NL257266A (en:Method)
DE1178763B (de) 1964-09-24

Similar Documents

Publication Publication Date Title
US2723239A (en) Ferrospinel compositions
US2762777A (en) Permanent magnet and method of making the same
US3565806A (en) Manganese zinc ferrite core with high initial permeability
GB780278A (en) Improvements in or relating to methods of manufacturing non-metallic anisotropic permanent magnets
US3054752A (en) Square loop magnetic manganeseferrite material and manufacture thereof
US3055833A (en) Mixed ferrospinels
US3038860A (en) Lithium nickel ferrites
US2977312A (en) Ferromagnetic material
US2565058A (en) Ceramic magnetic materials with high saturation-flux density
US3370011A (en) Lithium magnesium ferrite memory core material
US2982948A (en) Multi-material ferrite cores
US3372123A (en) Method for manufacturing lithiumnickel-manganese ferrite magnetic memory cores
US2981689A (en) Square loop ferrites
US2950251A (en) Magnetic materials having rectangular hysteresis characteristics
US3034987A (en) Magnetic cores
US2988508A (en) Copper containing ferrite cores
US3630912A (en) Lithium titanium bismuth ferrites
US3031407A (en) Method of producing ferrite bodies
US3083164A (en) Method of producing ferrite bodies
US3065182A (en) Low flux density ferromagnetic material
US3036008A (en) Permanent magnet ferrite
US3030306A (en) Method of manufacturing a magnet core having an approximately-rectangular hysteresis loop
US3039966A (en) Square loop ferromagnetic material
US3293184A (en) Method for making a ferromagnetic memory core
US3717578A (en) Annular magnet core built up from a soft magnetic ferrite material and method of manufacturing the same