Electrically conductive article

An article having a light transmission of at least 50 per cent comprises a body of glassy siliceous material and a continuous layer on the body composed of an intimate molecular mixture of a metal and a metallic inorganic dielectric compound, the proportions of the layer being such that it is electrically conductive. The layer may be used to cause adherence of a pure metal layer directly to the siliceous base or may be used to cause adherence of a protective layer, e.g. silica, to an underlying metallic conducting layer. The metal forming the layer may be Cu, Au, Ag, Al, Pt, Rh, Ni, Fe, Co, Sn, Ti, Cd, Zn, Cr, Mg, Mn, Pd, Zr, V, Pb, As, Sb, Bi or the alloys "Monel" (Registered Trade Mark) and "Nichrome" (Registered Trade Mark). The dielectric compound employed may be: an oxide, sulphide, sulphate, selenide, selenate, telluride, tellurate or halide e.g. of Pb, Ag, Al, Mg, Zn, Cd, Sb, Bi, Hg, Cu, Pt or Pd; a sulphide of Sn, As, Fe or Ni; lithium fluoride; mixed oxides or compounds e.g. spinels. The layer may be put on the base by thermal deposition or by sputtering and the article may be baked e.g. at 600 DEG F., after the coating step. A layer with the proportion of metal and dielectric uniform throughout may be obtained (a) by simultaneous thermal deposition of metal and dielectric on to the base or (b) by the thermal evaporation of a mixture of non-oxidisable metal, e.g. Au, and an oxidisable metal, e.g. Al, or compound e.g. sulphide, on to the base followed by oxidisation of the metal or compound. A layer in which the proportion of metal and dielectric varies throughout its thickness may be obtained by thermal evaporation of a mixture of metal and dielectric compound which have different evaporation rates. Numerous examples are given of the production of articles e.g. windscreens and radar plotting screens. Specification 693,127 [Group III] is referred to.