| 摘要 |
<PICT:1117002/C1/1> Glasses which have semi-conductive properties and which may be reddish in colour or opaque are formed from antimony, sulphur and iodine in the proportions covered by the shaded areas of the ternary diagram. Provided 15 atomic per cent antimony and 24 atomic per cent sulphur are present antimony may be replaced by 15% indium, 10% silica, 20% germanium, 15% tin, 10% lead, 8% phosphorus, 24% arsenic and/or 2% bismuth and sulphur may be replaced by 12% selenium (or 24% selenium if arsenic is present) and/or 12% tellurium. Thin wafers of the glasses have an initially very high resistance and can be switched to a low resistance state by an electric pulse of suitable voltage and duration. They can then be switched to a high resistance state (lower than the initial resistance) by a pulse of lower voltage. The glasses may be made by melting the component elements or compounds formed from these elements in a closed or open tube and if necessary chilling rapidly to preserve the vitreous state. Coatings on metal, e.g. aluminium may be obtained by dipping in the molten glass. They also have the ability to wet ceramic materials. Beads may be made by dropping or blowing cullet through a high temperature zone in an atmosphere of nitrogen or directly from molten glass. Fibres may be made by jet-blowing a stream of molten glass and filaments by rapid cooling of glass drawn through a die. Thin plates and flakes and small jewelling "gems" can be made by casting a thin layer on a cool steel surface. A number of composition examples are given. |
