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In this research, the effect of heat treatment on the hardness and wear resistance of the composite duplex electroless coating of Ni-P/Ni-B containing BN nanoparticles has been investigated. For this purpose, a 15-micron Ni-P electroless coating and a 10-micron Ni-B-BN electroless coating were applied on the surfaces of samples. The coated samples were heat treated for 1 h at 300, 400 and 500• C. The effect of heat treatment on the morphology, hardness and wear behavior of the coatings was studied by the SEM, XRD, and pin-on-disc wear test. Tafel polarization test showed that the presence of the Ni-P electroless coating improves the corrosion resistance of the duplex coating. Moreover, the microhardness of coating was evaluated before and after the heat treatment via the Vickers microhardness testing machine to evaluate the effect of heat treatment temperature on the hardness of the samples. The results indicated that the produced coating morphology was cauliflower-shaped. The heat treatment at 400• C creates the nano-crystalline structure, thereby increasing the hardness and wear resistance of the coating due to its change from the amorphous to crystalline structure and the production of the Ni3B hard phase. The Tafel polarization test revealed that the Ni-P layer improved the corrosion resistance of the two-layer composite coating. K e y w o r d s : nickel-boron electroless coating, heat treatment, corrosion, hardness, wear resistance

The ventilation heat loss in a typical unimproved UK dwelling is approximately equal to the conduction loss; therefore draught-proofing measures should form part of any energy refurbishment package. This will improve the building's air permeability but risks incurring additional energy costs associated with the need to provide controlled ventilation to maintain indoor air quality. This paper aims to determine the point at which the air permeability of the building improves the energy performance by enough to justify the increase in energy associated with the installation of mechanical ventilation with heat recovery (MVHR). A 1930's style semi-detached house, representative of a large proportion of solid wall dwellings in the UK, has been improved by a package of measures including MVHR. The building air tightness plays a critical role in reducing the building energy consumption and CO 2 emissions.

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