| 摘要 |
<p>1388733 Metal with porous coating layer UNIVERSAL OIL PRODUCTS CO 20 June 1972 [21 June 1971] 28740/72 Heading C7F Particles of a metallic primary material are uniformly mixed with particles of a secondary material; the mixture is flame-sprayed on a metal substrate to form thereon a molecularly bonded but inhomogeneous layer of the primary material containing regions of pure secondary material not alloyed with, nor inter-diffused with the primary material, and thereafter the secondary material is eliminated from regions of pure secondary material to provide a porous continuously-bonded layer of primary material bonded to the substrate. Typically, a Cu tube is flame-sprayed with a mixture of 80-95 wt per cent primary material and 20-50 wt per cent secondary material, e.g. 90% Cu and 10% Zn, and subsequently immersed in 10% HCl at room temperature for 3 hours to leach out the Zn and leave a porous Cu layer useful as a heatexchange surface. A plastics such as PTFE may be used as the secondary material, and leached out using an organic solvent.</p> |
