Ceramics and glasses are often the best, or only, material choice for an application. Their combination of high strength, temperature resistance, surface hardness, and transparency-by-design make their use more prevalent than one might expect.

Rimkus uses optimum methods to identify modes of failure or characterize these materials for their composition and physical properties. With specialized expertise in window glass and e-glass, we can identify the source and origin of scratches, discoloration, or permanent chemical etching.

Rimkus has the analytical competence to measure outgassing, binder loss, or absorbed fluids in ceramics and glass. We offer imaging of fracture surfaces, stains, and surface chemistry; cross-sectioning to evaluate cracks, voids, and intergranular phases; characterization of thin layer coatings; identification of organic contaminants absorbed during service; and measurement of decomposition due to oxygen, fluorine, and chlorine.

2 Case studies

1. Permanently etched window glass

Background: Shortly after a cleaning service had power washed the siding of a house with large, customized windows, the window glass was found to be opaque in patterns that resembled splashing. Cleaning the windows did not offer any improvement.

Services Provided: Rimkus was retained to examine the windows and determine if there was permanent damage and how extensive the damage to the windows was in terms of cost. Rimkus inspected approximately 25 customized windows on the inside and outside surfaces in accordance with ASTM (American Society for Testing and Materials) standards.

Several were permanently etched by chemicals. A survey was completed that identified how many windows would have to be replaced. Acetate replicas from the windows were taken to identify the depth of the damage and to pull off chemical residues for analysis.

Rimkus concluded:

• The same chemicals used by the cleaning company were identified in the residues taken from the windows.
• If the cleaning company had thoroughly rinsed the windows on the same day that they power washed the house siding, there would not have been damage to the glass. It was a week later that the windows were rinsed. By then the windows were permanently etched.
• Less than half the windows had enough damage to require replacement.

2. Explosive fracturing of engineered stone bathtub

Background: An elderly woman was filling a recently installed bathtub, fabricated from engineered stone. She was in the kitchen when she heard what she thought was an explosion. When she entered the bathroom, the bathtub had a large fracture, from top to bottom, and water had flooded the floor.

Services Provided: Rimkus was retained to examine the bathtub and determine the cause and origin of the fracture. We used a flexible scope to inspect behind and underneath the bathtub around the fracture. A square section was removed using a circular saw to allow for a flexible hose from the back. The fracture initiated at the corner of the square.

Rimkus concluded:

• Engineered stone is under a high degree of residual stress because of the manufacturing process. Stone powder is mixed with a polymer and poured into a mold. As the polymer cures and shrinks, stress develops.
• The plumber had disregarded the installation instructions that emphasized, under no circumstances, should the engineered stone be cut or drilled.
• The plumber’s saw cut created a stress concentration at the sharp corner of the square. As the bathtub was filling with hot water, the high residual stress at the sharp cut released, forming a crack that rapidly propagated across the tub, sounding like an explosion.