Glass composition and coated article

摘要

A single phase glassy composition comprises a first component consisting of arsenic or arsenic containing at least one of the elements antimony and bismuth, a second component consisting of sulphur or sulphur containing at least one of the elements selenium and tellurium, a third component consisting of iodine, or bromine or iodine and bromine, or iodine and/or bromine containing at least one of the elements fluorine and chlorine, with or without a fourth component consisting of at least one of the elements lead, gallium, indium and thallium, the balance, if any, consisting of other compatible components. Fig. 1 gives the range of compositions of the As-S-I system, the I being replaceable by Br, these systems giving the preferred compositions. Up to 20 mol. per cent of the S and As may be replaced by respectively Se and/or Te and Sb and/or Bi. As shown in Fig. 5C, a diode device 40 is encapsulated by molten glasseous material 48 contained in a glass, metal or ceramic receptacle 47 which forms a close fitting joint with a metallic header 44 to form part of the final assembly. In a further construction, not shown, the entire diode, header and lower parts of electrodes 45, 46 are encapsulated, the glasseous material being in a large container and the device being withdrawn with adhering glasseous material. The coating may also be deposited by brushing, spraying or vapour deposition. As shown in Fig. 7B, a semi-conductor device 75 attached to heat sink 76 with electrodes 77, 78 has a cylindrical glasseous material pre-form 79 of pressed powder is placed over the join of device 75 with electrode 78 and raised to its flow temperature, the glasseous material deforming to the shape shown to bond with the heat sink 76. The glasseous material forms hermetic seals with Al, Ag, An, Pt, Ta, Mo, Ni, W, brass and other iron and aluminium alloys. Specification 923,338 is referred to.ALSO:A glassy composition consists of As, S and either I or Br, optionally with one or more of Se, Tl, Sb, Bi, F and Cl replacing the S, As, I or Br and optionally with a fourth component consisting of one or more of Pb, Ga, In and Th, and the whole range of Fig. 1 and the combined and substituted systems may all be vapour deposited, particularly the points 12. Relatively thick coatings may be deposited, either from a glassy or powdered source and on to a heated or cold substrate. The material forms good seals with Al, Ag, Au, Pt, Ta, Mo, Ni, W, brass and iron and aluminium alloys. Specification 923,338 is referred to.