In this work, glass-ceramics were produced with mechanical and physical properties, using recycled glass powder from windshields as raw material. The glass powder was formed and sintered at temperatures 600, 650, 700, 750, and 800°C. Pieces were also produced with the addition of niobium oxide to the glass powder. The flexural strength and the Archimedes density of the produced parts were determined. The reliability of the results was evaluated by the Weibull statistic. X-ray diffraction was performed. Maximum flexural strength was 77.64 MPa at 750°C, with the addition of niobium oxide at 43.86 MPa at 700°C. X-ray diffraction showed crystalline structures in the specimens with the addition of the nucleating agent, confirming the production of glass-ceramics in this composition. The pure glass powder only crystallized from 750°C. The Nb2O5 favors the formation of crystalline structures in the vitreous matrix at low temperatures and with piezoelectric structures.
Fiber-reinforced polymers (FRPs) combine characteristics of polymers and fibers to obtain a material with high mechanical strength and stiffness together with low specific mass and good corrosion resistance. The use of FRPs is growing as an alternative to metals in the automotive, aerospace and civil construction industries. Since adhesive bonded joints are an excellent way of joining materials due to the better load distribution, the use of FRPs for this purpose has been the objective of many studies about durability and structural safety. In service, environmental factors, including temperature, humidity, UV exposure and salt spray, can degrade materials, leading to unexpected failures. Since joints in service are subject to these multiple and uncontrolled adverse conditions, FRP adhesive bonded joint degradation has been studied by experiments that simulate these adverse environmental conditions. The combined analysis of the effect of environmental factors on the joint and the materials of each component allows predicting the system performance. In addition, optimal design parameters, such as the thickness of the adhesive, overlap length, materials and manufacturing processes, may be different according to the target application of the joint. Therefore, the achievement of optimal design parameters depends on the understanding of joint behavior in service. Based on analysis of the contribution of researchers in the specialized literature on adhesive joints and FRPs, this article reviews the main findings on degradation of adhesive joints and their components. Research topics for optimization of adhesive joint systems are also discussed.
The objective of this work is the production and characterization of glass-ceramic with recycled glass powder and 4% (w/w) of cerium dioxide. Eleven groups were defined with conformation pressure of 11.6 and 25.8 MPa, and cerium dioxide addition. The sintering temperatures of 650, 675, 700 and 750 °C were used. The raw material was formed into a mold with a uniaxial pressure. The density was measured by the Archimedes principle. The water absorption of the groups was also determined, as linear contraction percentage and the crystalline structure. The flexural strength was obtained by the three-point bending test and the results analyzed by the Weibull analysis. The specimens presented density ranging from 1.99 to 2.38 g/cm3. Increasing the temperature provided an increase in the density of the specimens and the flexural strength. At higher sintering temperature, this behavior was not observed. The highest flexural strength was 63.55 MPa, obtained at the sintering temperature of 700 ºC, conformed with 25.8 MPa, only glass powder. The increase in the forming pressure favored crystallization. The addition of cerium dioxide favored for the increase density and the Weibull modulus, but decrease of the flexural strength.
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