| 摘要 |
PURPOSE:To obtain easily a heat exchanger formed of aluminum and having excellent corrosion resistance by brazing and joining members with a brazing filler metal formed by mixing potassium fluoroaluminate and zinc fluoride or zinc oxide at an adequate rate and suspending the mixture in water. CONSTITUTION:Potassium fluoroaluminate and zinc fluoride, zinc oxide or a zinc compd. consisting of a mixture composed thereof are mixed at (95-60):(5- 40) by weight and the mixture is suspended in water. The suspension is stuck to the surface of members for constituting a heat exchanger formed of aluminum and is dried, then the members are heated to a prescribed atmosphere in a non- oxidzing atmosphere to melt the brazing filler metal, thereby brazing and joining said members and obtaining the heat exchanger formed of aluminum. The above-mentioned potassium fluoroaluminate consists of a mixture composed of K3AlF6 and KAlF4 obtd. by melting KF and AlF3 and is preferably composed approximately to an eutectic compsn. so as to have the low m.p. as near as the eutectic point as possible. |
