Platinum alumnide coatings have been produced by first plating a thin layer of platinum usinq a fused salt platinum plating technique and then pack aluminizing using powder packs containingAl, NH4 C1 and Al 2 0 3 or Ni 2A1 3 , NH4 C1 and Al 203 . The chemistry and morphology of these coatings on IN-738 superalloy both in the ascoated and in the subsequently heat treated condition have been studied. The coating morphology and chemistry are highly dependent upon the thickness of the platinum layer, pack activity and time of processing. A relatively thick platinum layer (l0 pm) produced a coating with an outer Pt2A13 layer above other narrow layers. The Pt concentration decreases towards zero as the diffusion zone is approached. A second type, usually formed with a thin (5 pm) Pt layer is characterised by a marked interaction with the substrate. An outer Pt/U 2 layer is followed by a layer of NiAl containing fine precipitates of a chromiumtungsten rich phase. A lamella-like layer hiqh in chromium and other refractory elements exists at the coating/substrate interface in most of the as-coated samples. A third type of coating has been produced by a post-platinising heat treatment process prior to aluminizing. This type of coating is characterised by an outer duplex layer of PtAl 2 and Ni/U. Heat treatment of the as-formed coating results in interdiffusion between Al , Ni and Pt to produce an overall thickening of the coating layer and a decrease in the coating Al concentration. Thus a (Pt,Ni) Al or (Ni,Pt) Al outer layer may develop after heat treating these types of coatings at 1000°C for up to 1200 hours. In addition to this Widmanstatten sigma phase plates extending into the substrate are normally found beneath the outer layer after several hours' of heat treatment. Diffusion paths on pseudo-ternary phase diagrams are made to represent the phase constitution of the as-formed coatings. Isothermal oxidation tests in an oxygen atmosphere between 800 - 1000°C of different Pt-Al surfaces have been studied and the result of tests showed that the incorporation of Pt into the aluminide coatings enhance the oxidation resistance (particularly at 1000°C). Furthermore, thermal cyclic oxidation tests showed a remarkable improvement in oxide adherence over the simple aluminides.

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This research was initiated a result of a proposition described by Cleland and King in 1983. They proposed that the management of a portfolio-of-projects could be achieveda s a by-product of using a MIS containing project-management data. The hypothesis in this research takes their proposition further. It contends that the application of Pareto-based heuristics in the management of a portfolio-of-projects can improve on their approach. The research has been undertaken in Hong Kong. However, a review of the literature defines Hong Kong as a 'city-state' construction industry that is shown to be similar to national industries elsewhere. On this basis, the research establishes its validity for the general-case. Two qualitative surveys have been completed to identify the current methods used by Hong Kong contractors and by Hong Kong consultants for the management of their portfolios-of-projects. These elements of the research did not find evidence that in general, firms used a MIS that transformed project-level performance data to manage portfolios-of-projects. In this respect, there was no notable evidence of the adoption of the project-to-portfolio MIS data-pipeline described by Cleland and King. These surveys did not provide evidence that the commonly used 'individual review' or 'spreadsheet analysis' of multi-project data for portfolio management included prioritisation to identify projects of most significance to the outcome of the portfolio. Empirical data from the public works element of the Hong Kong construction industry is used in simulations of portfolio management to test the hypothesis along with a longitudinal grounded case study of the implementation of a portfolio/project MIS within the Hong Kong Government (HKG SAR). This case study provided practical experimentation through the quantitative measurement of 'before' and 'after' effects of a change to project-based multi-project management techniques that fitted the Cleland and King model. A qualitative survey has been completed to assess the degree of success and User satisfaction with this practical experimentation. The results of these elements of the research are taken to mean that the hypothesis is supported in principle. The final element of the research uses the empirical data to investigate the effectiveness of basing success for the portfolio-of-projects largely on the outcome of the important projects within the portfolio. Monte Carlo techniques are used to simulate an achievable excellent performance for the projects deemed as significant within the portfolio whilst the outcome for the other projects is unchanged. The simulated improved performance for the significant projects is based upon a derived probability-distribution-function (PDF) that represents the top twenty percent of project achievement for the portfolio-of-projects. The simulated outcome provides evidence in support of the hypothesis. With the exception of one of the ten cases tested, the theoretical application of excellent outcomes for the significant twenty percent of the number of projects using Monte Carlo techniques results in a worthwhile improved outcome for the portfolio as a whole. In the exceptional case, the actual result was already in agreement with the theoretical proposition. All ten cases, thereby showed the hypothesis to be true within the specifics and constraints of this research.