Biocorrosion and biodeterioration of some materials used in electrical engineering

Radu, Elena; Mitrea, Sorina; Pătroi, Delia; Voina, Andreea; Moscaliuc, Hermina; Lıngvay, Iosif

doi:10.1109/demisee.2016.7530483

Cited by 6 publications

(6 citation statements)

References 22 publications

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“…The fungal species identified from both mixed inoculums were Aspergillus niger (black) and Chaetomium globosum (white) on L-G and L-S samples, while for L-528 sample besides these species (Aspergillus niger and Chaetomium globosum), was also Trichoderma viride as seen in Figures 1 to 3 and from the details recorded with the USB microscope (shown in figs. [4][5][6].…”

Section: Resultsmentioning

confidence: 99%

“…The lacquers based on synthetic polymers have many applications in electrical engineering such as layers of corrosion protection, electro-insulating films and / or impregnation of insulating materials, consolidation of magnetic core and windings of transformers and / or electric motors [1], etc. Under the concerted and synergistic action of the stress factors (electrical, thermal, climatic, mechanical -especially vibration, microbiological [2][3][4][5] etc.) specific to the exploitation environment of electrical equipment, the lacquers based on polymer materials suffer ageing processes that degrade their functional physical-chemical properties [6,7], which lead to the reduction of the equipment life.…”

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confidence: 99%

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Ageing of Some Lacquers Due to Microbiological Stress

Bors¹,

Lungulescu²,

Nicula³

et al. 2019

Mat.Plast.

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This paper shows the ageing study of some coatings and / or impregnation lacquers due to microbiological stress through fungal attack. Dielectric spectroscopy has shown that the dielectric losses of the investigated materials increase as result of microbiological ageing. The mean recorded increases are about 4 times for the alkyl-epoxy-melamine copolymer, 2 times for epoxy polymer and 1.5 times for urethane polymer in agreement with the mould coverage degree of about 20 %, 10 %, and 3 %, respectively. The fungal attack of the investigated polymers led to a decrease in volume resistivity of about 65 % for the alkyl-epoxy-melamine copolymer, 45 % for the epoxy polymer, and 14 % for polyurethane, in agreement with the increase of dielectric losses and degree of mold coverage of the samples. FTIR determinations have shown that fungal attack significantly increased the number of aliphatic -OH and C-H bonds and decreased the number of C-O bonds, respectively of C-O-C oxiran groups and C-C aromatic bonds. DSC thermograms recorded at different temperature ranges and the activation energies calculation for first major oxidation process indicate that after the fungal attack the thermooxidative reactivity of the investigated polymers increases.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Ageing of Some Lacquers Due to Microbiological Stress

Bors¹,

Lungulescu²,

Nicula³

et al. 2019

Mat.Plast.

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“…Electro-insulating fluids based on mineral oils [54] are traditionally used in electrical equipment, which, although having adequate dielectric and thermal performance at a relatively low price, presents a number of drawbacks to electro-insulating fluids based on vegetable esters (recently developed and tested [55][56][57][58][59][60][61][62][63][64][65][66][67][68]) such as: relatively low flammability point (up to 135 °C) -high fire risk [39], degradation of cellulose from electro-insulating paper with furans formation, very low biodegradability [69].…”

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confidence: 99%

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

Lıngvay¹,

Bors²,

Ungureanu³

et al. 2018

Rev. Chim.

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For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

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“…This ageing occurs further to the interaction of these materials with their working environment and, also, as a consequence of the interaction between different materials. Thus, the degradation of the paint coatings applied on metallic parts (under the direct action of the different environment factors [13][14][15][16][17] including the microbiological factors [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]) leads to * email: adrianambors@gmail.com; Phone: 0773917319 corrosion of these metallic parts -in some extreme cases, to the irreversible damage of the steel electrical pillars [33] or of the reinforced concrete electrical pillars [34][35][36][37].…”

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confidence: 99%

Ageing of Some Painting Materials Subjected to Thermal Treatment in Natural Esters

Rus¹,

Caramitu²,

Ungureanu³

et al. 2018

Mat.Plast.

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This paper describes the evaluation of the aging process of some polymeric painting materials subjected to a thermal treatment in electro insulating fluids, based on natural esters (vegetable oils). The paint layers surface morphology was comparatively characterized by FESEM technique, prior to the exposure, and after 1000 h of exposure to vegetable oil, heated at 130oC. The results show a substantial increase in the pulling resistances for all the painting materials subjected to this investigation, especially in the presence of the Kraft insulating paper and copper foil (inserted compulsory to emulate the actual working environment), due to an increase in the painting material adhesion, as well as an increase of the tensile strength of the paint layer. These findings may open new theoretical and practical research prospects, particularly in the field of preliminary treatments for materials used for heavy duty industrial transformers.

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Biocorrosion and biodeterioration of some materials used in electrical engineering

Cited by 6 publications

References 22 publications

Ageing of Some Lacquers Due to Microbiological Stress

Ageing of Some Lacquers Due to Microbiological Stress

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

Ageing of Some Painting Materials Subjected to Thermal Treatment in Natural Esters

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