Laser cladding is an additive process wherein a laser source is used to melt metal-based powder or wire on to a metal substrate. A laser beam melts the additive material and a thin layer of the substrate (Figure 1). In this way metal or metal matrix composite (MMC) coatings with typically a thickness of the order of 1 mm are formed. Thanks to the superficial melting of the substrate, a strong metallurgical bond is formed between substrate and coating. With a low and local heat input, laser cladding is very well suited for the treatment of heat sensitive materials and components. Deformation of the component is limited and the heat affected zone is small. The high cooling rate during laser treatment results in coatings with a fine microstructure and minimal reaction between the ceramic and metallic phase in case of MMC coatings. After deposition, machining of the component to its final dimensions is mostly required. As laser source, different types of lasers can be used: CO2, Nd:YAG, diode, disk or fiber laser. The former two lasers are the most commonly used lasers in materials processing by laser welding and laser cutting. However, there is currently a strong development in new, more compact and more efficient lasers: the diode, disk and fiber laser. The results presented in this paper are obtained using a diode laser as heat source. As mentioned earlier, the laser cladding process enables the treatment of heat sensitive materials and deformation sensitive components, which cannot be processed by other techniques like conventional welding. The technique is increasingly being used in industry as a pro-active technology for corrosion and wear protection and as a reactive technology for repair of worn components. In both aspects, laser cladding is a technology contributing to costeffective maintenance.
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