| 摘要 |
<p>1282106 Manganese dioxide WESTERN ELECTRIC CO Inc 14 Aug 1969 [14 Aug 1968 19 May 1969] 40751/69 Heading C1A MnO 2 is deposited on a substrate, which is immersed in a permanganate solution of 0À1- 1À0 M concn. and pH less than 7, by addition of a reducing agent at a rate such that a dense adherent film of MnO 2 is formed. Na or KMnO 4 are preferred at concns. of 0À1-0À5 M (or 0À3- 0À5 M for continuous operation). Reducing agents specified are MeOH (preferred), NO 2 solutions, nitric, oxalic and formic acids, and formaldehyde and their homologues, used in aqueous solutions of 8-100% w./w. The reducing agent is added, with vigorous stirring, over a period of at least 3 mins., such that MnO 2 is deposited linearly at a rate of not more than 10 Š/sec. With nitric acid the rate of addition depends on the dissolved NO 2 content, but in general the rate should be not greater than 0À1 M/min. per litre of soln. With MeOH this rate should be less than 0À01, preferably less than 0À004 M/min./litre. To achieve a suitable pH acid may be added. Acids specified are nitric, sulphuric, hydrochloric and acetic. The temperature should be in the range 50-100‹ C. A wide variety of substrates may be treated, including glass, metallic, organic (polymer), and inorganic materials with rough or smooth surfaces.</p> |
