Bronze coating is a variant of flame spraying according to DIN EN 657/DIN EN ISO 14919 for all elements suitable for bronze coating Chromed or nitrated elements are unsuitable, amongst others. During bronze coating a 1/8" bronze wire is melted by a flame in wire flame spraying or arc spraying and finely pulverised on the work piece with pressed air.
The particles in bronze coating build a micro porous coating on the work piece that has been pre-treated by sand blasting SA3 according to DIN 55928 part 4. The bronze coated surface is very absorbent and can be additionally sealed with synthetic resin. Immersion or brushing with oil is however more recommended in view of the application examples.
Recommended minimum coating strengths are 100 µm to 300 µm for bronze coatings. These can be made up to 3000 µm at the request of the client however.
The raw materials for bronze coating are specified according to DIN EN ISO 14919 Tab.6.
Bronze coating generates smoke and dust and therefore the work should be carried out by qualified, certified staff to guarantee environmental and employment protection in compliance with DVS2314.
Bronze coating is applied for its excellent sliding and dry running features for example as bearing bronze, piston set, tool machine shafts, sliding surfaces on tool machines (bronze guides). The microporosity of the bronze coating generates a good oil and grease distribution. Hardness through wire flame spraying ca. 65HB and with HVOF bronze is also clearly higher. Bronze coating is applicable up to 250°C.
The advantage of bronze coating (ca. 60°C) also in comparison with bronze welding (at ca.450°C) is that the thermal exposure of the work piece can be disregarded and deformations can be excluded in large surfaces too. The disadvantage is that hollow spaces or difficult accessible places (recipients, undercuts, inner pipes etc.) cannot be coated with bronze.