In the gas-turbine research field, superalloys are some of the most widely used materials as they offer excellent strength, particularly at extreme temperatures. Vital components such as combustion liners, transition pieces, blades, and vanes, which are often severely affected by wear, have been identified. These critical components are exposed to very high temperatures (ranging from 570 to 1300 °C) in hot-gas-path systems and are generally subjected to heavy repair processes for maintenance works. Major degradation such as abrasive wear and fretting fatigue wear are predominant mechanisms in combustion liners and transition pieces during start–stop or peaking operation, resulting in high cost if inadequately protected. Another type of wear-like erosion is also prominent in turbine blades and vanes. Nimonic 263, Hastelloy X, and GTD 111 are examples of superalloys used in the gas-turbine industry. This review covers the development of hardface coatings used to protect the surfaces of components from wear and erosion. The application of hardface coatings helps reduce friction and wear, which can increase the lifespan of materials. Moreover, chromium carbide and Stellite 6 hardface coatings are widely used for hot-section components in gas turbines because they offer excellent resistance against wear and erosion. The effectiveness of these coatings to mitigate wear and increase the performance is further investigated. We also discuss in detail the current developments in combining these coating with other hard particles to improve wear resistance. The principles of this coating development can be extended to other high-temperature applications in the power-generation industry.

The water quality of rivers in Cameron Highlands has deteriorated significantly due to land clearing for agriculture, excessive usage of pesticides and fertilizers as well as construction activities in rapidly developing urban areas. It has been investigated that non-point pollution sources (NPSs) are the main contributor of this water quality drop. NPSs are diverse and hard to identify and therefore they are difficult to estimate. Therefore, Geographical Information Systems (GIS) was used to provide an extensive approach to evaluate land use and other mapping characteristics to explain the spatial distribution of NPSs of contamination in Cameron Highlands. The method to assess pollution sources has been developed using Cameron Highlands Master Plan (2006)(2007)(2008)(2009)(2010) for integrating GIS databases, as well as pollution loads in the area of study. The results show highest annual runoff is created by forest, 3.56×10 8 m 3 /yr followed by urban development, 1.46×10 8 m 3 /yr. Furthermore, urban development causes highest BOD load (1.31×10 6 kgBOD/yr) while agricultural activities and forest contribute the highest annual loads for phosphorus (6.91×10 4 kgP/yr) and nitrogen (2.50×10 5 kgN/yr), respectively. Therefore, Non-structural management was recommended for the study area, which includes establish and provide technical advisory services unit, develop demonstration farms and provide incentives to encourage farmers in implementing sustainable agricultural management practices.

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Wear is the main problem in gas turbine combustor components. The mating surfaces experience surface degradation affected by wear damage. The main mechanisms of wear occurred on combustor components could be adhesive wear, abrasive wear, and fretting wear. Wear resistant materials such as Haynes 25 (L605) and Stelitte 6 were selected to be used in reducing wear damage especially on bull horn, transition piece and flow sleeve of combustor components. The reduction of wear on combustor components can be described as the extension of combustion inspection interval of a gas turbine. It is concluded that wear on combustor components can be reduced by the applications of wear resistant materials on the components.