Showing papers on "Sodium dichromate published in 1970"
TL;DR: In this paper, the surface chromium composition of tin plate treated cathodically in sodium dichromate solution was analyzed by three methods: (a) alkali stripping, (b) acid stripping, and (c) treatment with bromine methanol solution.
Abstract: The surface chromium composition of tin plate treated cathodically in sodium dichromate solution was analyzed by three methods: (a) alkali stripping, (b) acid stripping, and (c) treatment with bromine methanol solution. It is suggested that the surface chromium insoluble in alkali is anhydrous chromic oxide, while that soluble in alkali is hydrated chromic oxide. The potential time curves from galvanostatic anodic treatment of tin plate cannot be interpreted in the simplistic manner commonly accepted for tin‐free steels with a chromium‐chromium oxide coating.
8 citations
Patent•
22 Jun 1970TL;DR: In this paper, a preferred solution of sodium dichromate, sulfuric acid, and orthophosphoric acid maintained at a pH of less than one is used to etch away sharp edges (burrs) remaining after a copper clad epoxy-glass laminate has been drilled and to condition the epoxy glass for metal deposition.
Abstract: A preferred solution of sodium dichromate, sulfuric acid, and orthophosphoric acid maintained at a pH of less than one is used to etch away sharp edges (burrs) remaining after a copper clad epoxy-glass laminate has been drilled and to condition the epoxy glass for metal deposition.
6 citations
Patent•
04 Dec 1970
TL;DR: A method of preparing a liquid self-hardening mixture for making casting moulds and cores comprises mixing together: (i) a filler, (ii) a binder comprising at least one salt of lignosulphonic acid (sulphite lye); (iii) a foaming agent; (iv) a solidifying agent comprising a hexavalent chromium compound or a persulphate; (v) at least water-soluble inorganic compound of copper, iron or aluminium; and (vi) water as mentioned in this paper.
Abstract: 1293837 Foundry mould compositions VSESOJUZNY PROEKTNO - KONSTRUKTORSKO - TEKHNOLOGICHESKY INSTITUT STROIDORMASH 4 Dec 1970 57786/70 Heading C3N A method of preparing a liquid self-hardening mixture for making casting moulds and cores comprises mixing together: (i) a filler; (ii) a binder comprising at least one salt of lignosulphonic acid (sulphite lye); (iii) a foaming agent; (iv) a solidifying agent comprising a hexavalent chromium compound or a persulphate; (v) at least one water-soluble inorganic compound of copper, iron or aluminium; and (vi) water. The hexavalent chromium compound may be chromic acid anhydride or sodium dichromate whilst the persulphate may be ammonium persulphate. Component (v) may be copper sulphate, ferric chloride or aluminium chloride and the foaming agent may be an alkylaryl sulphonate. The filler may be quartz sand optionally together with a minor proportion of refractory clay. Preferably the components are taken in the parts by weight quartz sand 92-100, refractory clay 8-0; binder containing salts oflignosulphonic acid (45-55% by weight aqueous solution) 1A5-8A0; foaming agent 0A1-6; solidifying agent 0A1-1A5; watersoluble inorganic compound 0A1-2A0; and additional water 0-5A0.
1 citations