| 摘要 |
<p>In metal spraying a flux is incorporated into the stream of gas and metal particles from the spray gun by feeding it to the gun as droplets of liquid suspended in a carrier gas, as a gas mixed with a carrier gas or in both such forms. The carrier gas may be a fuel gas, an oxidant, or both may be used to carry the flux. Alternatively a separate gas stream may be employed to carry the flux, or where a plasma flame or arc- or induction-heated propulsive gas is employed the flux may be carried by the plasma-forming or propulsive gas. The flux is preferably a volatile liquid, and is incorporated into the carrier gas by entrainment from a wick Fig. 3 (not shown) or by bubbling the gas through it. Where the metal sprayed is copper, or an alloy of copper such as phosphor bronze, aluminium bronze or brass, an alkyl borate may be employed as the flux. Methyl-, ethyl-, propyl- and isopropyl-borate, or any combination of these which form a volatile liquid fluxing agent may be used. Alternatively any of them may be mixed with a suitable alcohol such as an alkyl alcohol. Where aluminium or its alloys is sprayed the fluxing agent may be a volatile liquid containing a fluoride radical. The invention is stated to be applicable to the spraying of ferrous metals and of nickel and its alloys, the fluxing agent being in each case a volatile liquid which inhibits oxidation of the metal.</p> |
