| 摘要 |
<p>Mould mfr., for working thermoplastic and other synthetics, is affected by spraying a mould with metal, consisting of two or more layers of different metals. The first layer consists of a metal with a lower m.pt. pref. 47-400 degrees C e.g. a Sn-Bi alloy. The second layer has a coarser to cellular structure, and is pref. produced by adjusting the metal spray gun to spray particles of dia. 1-2mm. Pref. the coarser layer is formed by providing in the spray metal a propellant which releases gas under the action of heat and which inflates the particles of molten atomised metal in the flame of the spray gun on their path towards the mould, sintering them onto the mould in the foamed state. Pref. the propellant has a decompsn. temp.at which gas is released, above the m.pt. of the metal used.</p> |
