| 摘要 |
<p>1463427 Coating steel with zirconium nitride; alloy steel PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 11 April 1975 [16 April 1974] 14979/75 Headings C7A and C7F An austenitic steel containing more than 5 wt. per cent Ni, and which contains at least at its surface at least 0À1 wt. per cent N, is coated with zirconium nitride by contact with a molten saturated solution of Zr in Pb at at least 800‹C, the solution containing no Bi or Sn. If the nitrogen content of the steel is insufficient, it is prenitrided conventionally, e.g. by treatment with NH 3 . The molten Pb may contain 0À1 wt. per cent Zr; the coating temperature may be 850-1000‹C; the resulting layer may be 1Á thick, and the coated body used in the cooling system of a nuclear reactor, where molten lead is the circulating fluid; if Zr is added to this lead, the nitride coating is self-healing. The steel substrate may have one of these compositions: (1) 18 wt. per cent Cr, 11 % Ni, 0À03 % C, 0À2 % N, balance Fe or (2) 19-20 % Ni, 18À5-20 % Co, 20-22À5 % Cr, 2À5-3À5 Mo, 2-3 % W, 0À08-0À16 % C, 0À1-0À2 % N, 0À75-1À25 Nb + Ta, # 1 % Si, 1-2 % Mn, balance Fe.</p> |
