Short fiber spraying process of all‐oxide ceramic matrix composites: A parameter study

Abstract Fiber spraying processes have been established for polymer matrix composites for decades. In this study, we transferred an automated fiber spraying process to short fiber bundle‐reinforced Nextel 610/ Al ₂ O ₃ ‐ZrO ₂ oxide fiber composites (SF‐OFC). The effect of the processing factors travel height, spray angle, and movement speed on the specimen strength was analyzed in a full factorial experimental design. As a result, the significance of the travel height as well as the interaction between travel height and movement speed was demonstrated. Furthermore, the influence of the fiber length (14, 28, 56, and 112 mm) on the bending stress and strain was investigated. Independent of the used fiber length, the SF‐OFC exhibited an excellent quasi‐ductile fracture behavior with bending strains in the range of .6% and in‐plane isotropic material properties. The average bending strength increased from 133 ± 27 MPa with 14 mm fiber reinforcements to 163 ± 29 MPa with 112 mm fibers. The achieved bending strengths clearly exceeded the off‐axis properties of currently used fabric‐reinforced OFC. These properties, combined with the excellent drapability and cost effectiveness, make the novel material highly promising for industrial applications such as flame tubes, burner nozzles, kiln furnitures, or foundry components.