GB972812A - Improvements in or relating to optical elements and methods for making such elements - Google Patents

Improvements in or relating to optical elements and methods for making such elements

Info

Publication number
GB972812A
GB972812A GB3732260A GB3732260A GB972812A GB 972812 A GB972812 A GB 972812A GB 3732260 A GB3732260 A GB 3732260A GB 3732260 A GB3732260 A GB 3732260A GB 972812 A GB972812 A GB 972812A
Authority
GB
United Kingdom
Prior art keywords
mould
ring
vacuum
powder
block
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
Application number
GB3732260A
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.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of GB972812A publication Critical patent/GB972812A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/02—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of crystals, e.g. rock-salt, semi-conductors
    • 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
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • 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
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/553—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on fluorides
    • 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
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/64—Burning or sintering processes
    • C04B35/645—Pressure sintering

Abstract

<PICT:0972812/C1/1> An optical element of magnesium fluoride is made from pure microcrystalline magnesium fluoride powder by pressure between 10,000 and 25,000 pounds per square inch while maintaining <PICT:0972812/C1/2> the temperature thereof within the range 1150 DEG to 1420 DEG F. for a sufficient period to ensure it becomes homogeneous. As shown in Fig. 3, the magnesium fluoride powder 10 is placed in a mould comprising a ring mould 12, block 13, insulator 15 and block 16 secured in a base 16 and is pressed by a plunger 17 secured to a head 8 which is attached to the piston of an hydraulic press (not shown). The plunger 17 passes through a ring 18 secured to the head 8 by a metal bellows 20 forming a vacuum seal. A vacuum chamber 30 is formed around the mould by base 16, top plate 19 and cylinder 29 and connected by conduit 24 to a vacuum system. The mould 12 is closely surrounded by a cylinder 21 and heating coils 11 and the cylinder 29 is surrounded by cooling coils 25. The temperatures adjacent the moulding positions are measured by thermocouples 28 and 31. The materials used for the moulding parts, i.e. the mould 12, plunger 17 and block 13 may be of molybdenum, tungsten, graphite, high density alumina or super alloys. A gas, such as nitrogen or helium may be used in the chamber 30 in place of the vacuum. The operation is preferably as follows: cold pressing at 5000 lb. per square inch for a few minutes to compact the powder, removal of any loose powder and then heating the coils 11, while producing a vacuum in chamber 30 and the cooling coils 25 are operated, to a temperature of 1380 DEG F. and then applying pressure of 15,000 to 25,000 lb. per-square inch for from 40 to 60 minutes with the temperature held between 1380-1420 DEG F. To form a block 10 of magnesium fluoride hermetically sealed into a ring 40 of steel, the ring mould 12 is recessed to take the ring 40, the hot pressing causing the powder to seal to the steel. High-frequency heating may replace the heating coils shown in Fig. 3. Specification 913,175 is referred to.
GB3732260A 1959-10-29 1960-10-31 Improvements in or relating to optical elements and methods for making such elements Expired GB972812A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US84957159A 1959-10-29 1959-10-29

Publications (1)

Publication Number Publication Date
GB972812A true GB972812A (en) 1964-10-14

Family

ID=25306024

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3732260A Expired GB972812A (en) 1959-10-29 1960-10-31 Improvements in or relating to optical elements and methods for making such elements

Country Status (1)

Country Link
GB (1) GB972812A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111267214A (en) * 2020-02-27 2020-06-12 赵慧楠 Concrete block, manufacturing machine and manufacturing method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111267214A (en) * 2020-02-27 2020-06-12 赵慧楠 Concrete block, manufacturing machine and manufacturing method

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