title: The performance of thermally sprayed titanium based composite coatings in molten aluminium

authors: Salman, Asma Siddiq

subjects: mechanical milling

abstract: The service life of die and tool steels in contact with molten aluminium is important in the aluminium processing industry. This article describes an investigation of the efficiency of thermally sprayed Ti(Al,O)/Al₂O₃ and TiAl(O)/Al₂O₃ composite coatings in resisting aluminium soldering on H13 tool steel. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO₂ powders using different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity oxygen fuel (HVOF) technique onto an H13 steel substrate to produce composite coatings. The performance of the coatings was assessed in terms of Al soldering and liquid metal corrosion resistance after immersing in molten aluminium at a temperature of 700 ± 10 °C. The results of this study showed that composite coatings have a potential to act as a physical barrier to prevent aluminium attack on H13 tool steel. The nature of Al attack on H13 tool steel changed from generalised to more localised attack with the thermally sprayed coating. A Ti(Al,O)/Al₂O₃ composite coating was not attacked by molten aluminium, however localised attack on a H13 tool steel substrate was found to be caused by molten metal penetration through defects in the coating. Composite coating TiAl(O)/Al₂O₃ was attacked by molten aluminium resulting in dissolution of the coating. Composite coatings showed significantly lower dissolution in molten aluminium compared with the uncoated H13 steel. A Ti(Al,O)/Al₂O₃ composite coating was found to be a more effective protective coating than a TiAl(O)/Al₂O₃ composite coating due its greater resistance to molten aluminium attack.

text: The performance of thermally sprayed titanium based composite coatings in molten aluminium The service life of die and tool steels in contact with molten aluminium is important in the aluminium processing industry. This article describes an investigation of the efficiency of thermally sprayed Ti(Al,O)/Al₂O₃ and TiAl(O)/Al₂O₃ composite coatings in resisting aluminium soldering on H13 tool steel. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO₂ powders using different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity oxygen fuel (HVOF) technique onto an H13 steel substrate to produce composite coatings. The performance of the coatings was assessed in terms of Al soldering and liquid metal corrosion resistance after immersing in molten aluminium at a temperature of 700 ± 10 °C. The results of this study showed that composite coatings have a potential to act as a physical barrier to prevent aluminium attack on H13 tool steel. The nature of Al attack on H13 tool steel changed from generalised to more localised attack with the thermally sprayed coating. A Ti(Al,O)/Al₂O₃ composite coating was not attacked by molten aluminium, however localised attack on a H13 tool steel substrate was found to be caused by molten metal penetration through defects in the coating. Composite coating TiAl(O)/Al₂O₃ was attacked by molten aluminium resulting in dissolution of the coating. Composite coatings showed significantly lower dissolution in molten aluminium compared with the uncoated H13 steel. A Ti(Al,O)/Al₂O₃ composite coating was found to be a more effective protective coating than a TiAl(O)/Al₂O₃ composite coating due its greater resistance to molten aluminium attack.

year: 2011

title: Support: Can it be a value creation strategy for positive marketing?

authors: Supramaniam, Sivakumari

subjects: support-seeking behaviour

abstract: In pursuit of improving people's wellbeing and engaging in positive marketing, this paper addresses the application of Vickers' Appreciation System to deepen our understanding of how people comprehend their environment and respond to improve their situation. The paper highlights how companies can collaboratively engage in people's appreciation and support them in fulfilling their needs.

text: Support: Can it be a value creation strategy for positive marketing? In pursuit of improving people's wellbeing and engaging in positive marketing, this paper addresses the application of Vickers' Appreciation System to deepen our understanding of how people comprehend their environment and respond to improve their situation. The paper highlights how companies can collaboratively engage in people's appreciation and support them in fulfilling their needs.

year: 2012

title: Exploring synergies between Māori pedagogy and communicative language teaching

authors: Nock, Sophie

subjects: Māori language

abstract: The primary aim of this paper is to explore potential synergies between Māori pedagogy and what is known as 'communicative language teaching'. A brief outline of some changes and developments in approaches to language teaching and learning over the last few decades is followed by a summary of some of the main characteristics of communicative language teaching (CLT) and of different approaches to the conceptualization of Māori pedagogy. Some of the primary characteristics of communicative language teaching are then explored in the context of Māori pedagogy and it is argued that there are some important synergies between the two.

text: Exploring synergies between Māori pedagogy and communicative language teaching The primary aim of this paper is to explore potential synergies between Māori pedagogy and what is known as 'communicative language teaching'. A brief outline of some changes and developments in approaches to language teaching and learning over the last few decades is followed by a summary of some of the main characteristics of communicative language teaching (CLT) and of different approaches to the conceptualization of Māori pedagogy. Some of the primary characteristics of communicative language teaching are then explored in the context of Māori pedagogy and it is argued that there are some important synergies between the two.

year: 2008-11-30