Projects / Programmes
Anticorrosion coatings for electronic boards (ACORC)
| Code |
Science |
Field |
Subfield |
| 2.09.01 |
Engineering sciences and technologies |
Electronic components and technologies |
Materials for electronic components |
| Code |
Science |
Field |
| P352 |
Natural sciences and mathematics |
Surface and boundary layery chemistry |
| Code |
Science |
Field |
| 2.10 |
Engineering and Technology |
Nano-technology |
anticorrosion coatings, nano particles, electronic boards, sol-gel coatings, organic coatings
Researchers (12)
Organisations (4)
Abstract
The proposed project has a multidisciplinary character, since it combines nanotechnology, chemistry and electronics. Also four partners are coming from different fields, for example Iskratel is manufacturer of electronic equipment, Helios represents paint and coating industry, while NIC and FKKT are research institute and university partner. All partners have specific skills in their own areas of research or production and will join their efforts to address the corrosion issues raised by electronic board (EB) substrates and their protection. Namely, anticorrosion coatings for EBs should correspond to a unique set of corrosion-related issues, since EBs are composed of various materials (metals, alloys, soldering alloys,…). They are in the close proximity, which brings about great possibility for galvanic corrosion, corrosion of contact surfaces and joints or growth of dendritic silver. In addition, the surface of EBs are not flat, therefore they are difficult to cover homogeneously. Nowadays mostly conformal paint coatings (urethane, acrylic,...) are used for protection of EBs, but such coatings are expensive and usually do not offer satisfactory adhesion and protection ((10 years). It is believed that nanocomposite barrier coatings, consisting nanoparticles (SiO2, Al2O3, ZrO2,...) or polyhedral oligomeric silsesquioxanes (POSS), embedded either in organic polymers or sol-gel matrices are promising materials to successfully replace the conformal coatings. The essential part of the planned development in the proposed project is therefore the investigation and optimisation of possible preparation procedures and, in the final stage of the project, technological deposition issues of nanocomposite sol-gel and nanocomposite organic coatings.
Preparation of good nanocomposite coatings starts with an appropriate selection of precursors, nanoparticles, inhibitors and additives. Organic nanocoatings will mainly be studied on the basis of epoxy resin and nanoclay particles. As the network formers for sol-gel nanocomposite coatings various bis end-capped alkoxysilyl precursors that comprise also polydimethylsiloxane network bringing about the hydrophobic character of the precursor are planned. Nanoparticles will mainly be included as a pre-prepared species, and when non available in a nanosized form, we will explore the possibilities of their preparation with milling from micron-sized particles. Functionalization of surfaces of nanoparticles is planned to enable their interaction with the matrix. From this point of view, open cage POSS are of extreme importance since they can bind into sol-gel network via siloxane bonds. Another demanding issue connected with nanoparticles is their dispersion into the coating formulation, since in order to overcome the adhesion forces high stress intensities are required. The problems of localised corrosion on any small defect sites will be overcome by addition of inhibitors, either in the form of surface activated nanoparticles (i.e. CeO2 nanoparticles activated with cerium ions) or alkoxysilyl-functionalised benzimidazoles or benzotriazoles. The latter organic-inorganic inhibitors are capable to bind in the sol-gel matrix, which prevents their leakage from the system. Such inhibitors are new and were not tested in any anticorrosion coatings yet. The final chosen formulations for organic nanocomposite and/or sol-gel nanocomposite coatings will be optimised to perform also their deposition on conformal coating line Asymtek SL-940 available in Iskratel. In the frame of proposed project, apart from development of nanocomposite coatings, we will devote some strengths also to development of analytical approaches, among which we would like to stress ex-situ IR reflection-absorption and ex-situ Raman spectroelectrochemical measurements. Such measurements enable detection of bonds that are most prone to cleavage and therefore render possible the effective optimisation of coating formulations.
Significance for science
The significance of the results of this project for science can be found in two dimensions: - sinthesis of new compounds and novel protective coatings, - development of new analytical approaches. In the frame of this project we developed the synthesis of a new precursor, i.e. cyclic tetrasokoxane, which was alkoxysilyl functionalised. Consequently, it can enter into sol-gel processes and form crosslinked protective coatings. The investigations of cyclic tetrasiloxynes for the preparation of protective coatings are rare, actually there is know only one example in the literature. Namely, similar cyclic tetrasiloxane was introduced in resins for preparation of lacquers for cars. Till now there was no systematic study on the influence of the characteristic cyclic structure of tetrasiloxane on the eventual higher effectivity of protective coatings. We developed also new approaches for preparation of effective sol-gel protective coatings for metals/alloys, mostly with the application of various trialkoxysilanes as functional additives to cyclic tetrasiloxane. Secondly, there were developed cells for coupled analytical methods, i.e. in situ Raman spectroelectrochemistry and in situ electrochemical AFM cells. In both cases, the approaches were developed from scratch and were not available at our institute. The cells enable us to follow structural and morphological changes in protective layers while they are exposed to electrochemical treatment, also to large loads that can lead to degradation of the layers.
Significance for the country
The significane for Slovenia can be found in the part of the project that concerned the industrial partners. Namely, in both companies the development of new or improvement of already existing products was going on. The whole project was designed on the basis of the preparation of protective coatings for electronic boards that are produced or completed in Iskratel company. This company had started the development of protective coatings for electronic boards on a new coating line just before the beginning of this project. However, there still remain the questions about the lacquer that was used and about the possibilities of the use of additional new lacquers. Consequently, there was performed quite some analysis of lacquers that were used during this project, as well the analysis of coated electronic boards. There was performed also the study of degree of corrosion in various atmospheres, in which the boards are used. The company obtained information on both lacquers that they chose for production of protective coatings. Faculty for chemistry and chemical technology in addition analysed the thermal profiles that were used on coating lines and prepared the opinion on possible improvements. The project gave certain answers to this company and consequently also influenced the possibility of the launchment of the protected electronic boards to the market. At the same time, the Helios company developed new epoxy formulations that are appropriate for the preparation of coatings for electronic boards. The work was dedicated to the study of coating formation, choice of appropriate precursors and optimal ratio for the deposition on electronic boards. These formulations are option for introduction of new product into the production. In the frame of the project there was made a dissertation of Dr. Mirjana Rodošek, which influenced the education level. She got new knowledge that can be used in her future work.
Most important scientific results
Annual report
2013,
2014,
2015,
final report
Most important socioeconomically and culturally relevant results
Annual report
2013,
2014,
2015,
final report
