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Previous issue date: 2017-05-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A crescente demanda por produtos com maior performance, menor custo de fabrica??o, menos impactantes ao meio ambiente que sejam mais eficientes energeticamente, t?m fomentado pesquisas em diversas ?reas da nanoci?ncia e nanotecnologia (N&N), visando sobrepujar estas limita??es ou agregando as principais vantagens dos nanocomp?sitos e nanofluidos (NF) os quais tem sido extensivamente aplicados nas ind?strias. O objetivo deste trabalho foi estudar as caracter?sticas de nanolubrificantes (NL) aditivado com nanopart?culas (NPs) de ?ndio (In), para poder contribuir com a redu??o significativa do tamanho, peso e custos dos sistemas de transfer?ncia de calor, tendo estes uma melhor estabilidade mec?nica, uma menor resist?ncia ao atrito e desgaste, e que possuia uma melhor ader?ncia em regime de lubrifica??o limite. Para estes fins, ap?s a aquisi??o das NPs de In, foram preparados tr?s nanolubrificantes (NLs) distintos, adicionando-se 0,3 g/L aos ?leos de compressores de refrigera??o herm?ticos o ISO68, ISO32, e o Poliol ?ster (POE). Ap?s o processo de prepara??o que consiste na desfragmenta??o e homogeneiza??o, cada composto foi ensaiado em banho termost?tico e com o aux?lio de um re?metro e um condutiv?metro, foi mensurados os valores relativos ?s suas propriedades t?rmicas, para comprovar as propriedades requisitadas. A estabilidade mec?nica foi verificada atrav?s de compara??es cronol?gicas, potencial zeta e aglomera??o de part?culas, ap?s passou-se por ensaios de lubricidade utilizando-se os trib?metos de sonda com movimento alternado em alta frequ?ncia (High Frequency Reciprocating Rig ? HFRR) e ensaio de pino contra disco para an?lise de desempenho tribol?gico. Os corpos de prova dos ensaios foram analisados em MEV (Microscopia eletr?nica de varredura) e EDS (Espectr?metro de Dispers?o de Energia) para comprova??o dos resultados, onde foram realizadas analises dos modelos desenvolvidos, levando em considera??o par?metros como: coeficiente de fric??o, for?a de atrito, desgaste etetivo, composi??o final dos corpos de prova a aglomera??o das part?culas nos NLs, a temperatura e a viscosidade do fluido, e movimento Browniano das part?culas, entre outros. Os NLs compostos por In foram vi?veis, n?o se fazendo necess?ria a utiliza??o de tensoativos para melhorar a sua estabilidade, pois apresentaram resultados satisfat?rios nos ensaios tribol?gicos, mostrando-se com propriedades de lubrificantes de extrema press?o (EP), melhorando significativamente o desempenho tribol?gico. Assim, torna-se vi?vel a utiliza??o NLs gerados a partir de NP de In na lubrifica??o de compressores herm?ticos de refrigera??o. / The increasing demand for products with higher performance, lower manufacturing cost, less impactful to the environment and are more energy efficient, have fostered research in various areas of nanoscience and nanotechnology (N&N), aiming at overcoming these limitations or adding the main advantages of nanocomposites and nanofluids (NF) which have been extensively applied in industries. The objective of this work was to study the characteristics of nano-lubricants (NL) added with nanoparticles (NPs) of indium (In), In order to contribute to the significant reduction of the size, weight and costs of heat transfer systems, which have a better mechanical stability, a lower resistance to friction and wear, and a better adhesion in the limit lubrication regime. For these purposes, after the acquisition of In NPs, three separate nanolubrificantes (NLs) were prepared, adding 0.3 g / L to hermetic refrigeration compressor oils ISO68, ISO32, and Polyol Ester (POE). After the preparation process consisting of defragmentation and homogenization, each compound was tested in a thermostatic bath and with the aid of a rheometer and a conductivity meter, where the values relative to their thermal properties are measured, to verify the required properties. The mechanical stability was verified through chronological comparisons, Zeta potential and particle agglomeration, after being subjected to lubricity tests using probe tribromes with High Frequency Reciprocating Rig ? HFRR and pin-to-disk test for tribological performance analysis. The test specimens were analyzed in SEM (Scanning Electron Microscopy) and EDS (Energy Scattering Spectrometer) to prove the results, where analyzes of the developed models were carried out, taking into account parameters such as: Friction coefficient, friction force, wear resistance, final composition of the test specimens as well as the agglomeration of the particles in the NLs, temperature and viscosity of the fluid, and Brownian motion of the particles, among others. The NLs comprised of In were feasible, with the use of surfactants not being necessary to improve the stabilities, presented satisfactory results in the tribological tests, showing with properties of extreme pressure lubricants (EP), significantly improving the tribological performance. Thus, it becomes feasible to use NLs generated from NP of In in the lubrication of hermetic refrigeration compressors.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23647 |
| Date | 03 May 2017 |
| Creators | Sousa, Eduardo Henrique Viana de |
| Contributors | 20300190468, http://lattes.cnpq.br/9043538628554844, Almeida, Igor Marcel Gomes, 07039406438, http://lattes.cnpq.br/2914541046309057, Fontes, Lucio Angelo de Oliveira, 09443703491, http://lattes.cnpq.br/6626062514308083, Azevedo, Val?rio Fernandes de, 46804889487, http://lattes.cnpq.br/9300959808630479, Barbosa, Cleiton Rubens Formiga, Fontes, Francisco de Assis Oliveira |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA MEC?NICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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