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Publication
Caracterização reológica de massas lubrificantes de sulfonato de cálcio e de complexo de lítio
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Abstract(s)
O presente trabalho tem como objetivo avaliar o comportamento reológico de massas
lubrificantes formuladas com espessantes à base de sulfonato de cálcio e de complexo de lítio.
Com este objetivo, foi realizada uma caracterização detalhada das propriedades viscoelásticas,
da tensão de cedência e da resposta das massas à variação de temperatura e taxa de corte. Os
ensaios foram realizados com recurso a um reómetro em configuração cone-placa, permitindo
a análise de parâmetros como viscosidade dinâmica, módulos de armazenamento e de perda,
entre outros. Ainda neste estudo é fornecida uma visão em termos de energia, analisando a
dissipação e armazenamento de energia no processo de lubrificação. Os resultados indicam que
a massa com espessante à base de sulfonato de cálcio apresenta maior estabilidade térmica e
resistência mecânica, enquanto a massa à base de espessante de complexo de lítio demonstra
consistência inicial superior, mas maior sensibilidade a variações de temperatura. A análise
comparativa mostrou ainda que a escolha da massa lubrificante baseada no tipo de espessante,
influência diretamente a eficiência, durabilidade e comportamento tribológico da massa
lubrificante. Este estudo contribui para uma melhor compreensão do desempenho de massas
lubrificantes sob diferentes condições operacionais, podendo demonstrar-se um contributo
importante na seleção da massa lubrificante adequada à aplicação pretendida.
The present study aims to evaluate the rheological behavior of lubricating greases formulated with calcium sulphonate and lithium complex thickeners. For this purpose, was performed a detailed characterization of the viscoelastic properties, yield stress and response of the greases to temperature and shear rate variation. The tests were performed using a cone-plate rheometer, allowing the analysis of parameters such as dynamic viscosity, storage and loss moduli and others. This study also provides an overview in terms of energy, analyzing energy dissipation and storage in the lubrication process. The results indicate that the grease with calcium sulfonate thickener has greater thermal stability and mechanical resistance, while the grease based on lithium complex thickener demonstrates superior initial stiffness but greater sensitivity to temperature variations. The comparative analysis also showed that the choice of lubricant based on the type of thickener directly influences the efficiency, durability and tribological behavior of the lubricant. This study contributes to a better understanding of the performance of lubricants under different operating conditions and may prove to be an important contribution to the selection of the appropriate lubricant for the intended application.
The present study aims to evaluate the rheological behavior of lubricating greases formulated with calcium sulphonate and lithium complex thickeners. For this purpose, was performed a detailed characterization of the viscoelastic properties, yield stress and response of the greases to temperature and shear rate variation. The tests were performed using a cone-plate rheometer, allowing the analysis of parameters such as dynamic viscosity, storage and loss moduli and others. This study also provides an overview in terms of energy, analyzing energy dissipation and storage in the lubrication process. The results indicate that the grease with calcium sulfonate thickener has greater thermal stability and mechanical resistance, while the grease based on lithium complex thickener demonstrates superior initial stiffness but greater sensitivity to temperature variations. The comparative analysis also showed that the choice of lubricant based on the type of thickener directly influences the efficiency, durability and tribological behavior of the lubricant. This study contributes to a better understanding of the performance of lubricants under different operating conditions and may prove to be an important contribution to the selection of the appropriate lubricant for the intended application.
Description
Keywords
Rheology Lubricating greases Calcium sulphonate Lithium complex Elasticity Lubrication Reologia Massas lubrificantes Sulfato de cálcio Complexo de lítio Elasticidade Lubrificação