Aija Rautmane

High-temperature coatings are routinely exposed to pre-existing surface damage, yet their ability to sustain sliding contact after such damage remains insufficiently quantified. This study develops a damage-tolerant reliability-mapping workflow for physical vapour deposition (PVD) AlCrN coatings by intersecting controlled pre-scratch defects with dry sliding contact at room temperature, 500 °C and 800 °C. A multilayer AlCrN coating on 253 MA steel was first damaged by calibrated constant-load scratching (1.96–16.67 N) and then subjected to ball-on-disc sliding over an equivalent load range. Surface responses at the scratch–wear intersections were classified using an 18-event taxonomy and reduced to a scalar reliability index; conservative monotone safe envelopes were then extracted for each temperature. The results show a transition from damage-tolerant to failure-dominated behaviour as scratch severity, applied load and temperature increase. Mild pre-damage can be locally stabilised by debris compaction and oxide tribolayer formation, whereas deep pre-damage and high temperature promote delamination, substrate exposure and mechanically mixed oxides. At 800 °C, only two load pairs remained within the conservative contiguous safe envelope. The proposed framework goes beyond conventional adhesion or wear metrics by explicitly linking pre-existing damage to subsequent sliding response. The method provides a transferable screening concept for defect-sensitive tribological coatings.

The widespread use of epoxy resin (ER) in industry, owing to its excellent properties, aligns with the global shift toward greener resources and energy-efficient solutions, where utilizing metal oxides in 3D printed polymer parts can offer extended functionalities across various industries. ZnO concentrations in polyurethane acrylate composites impacted adhesion and thickness of DLP samples, with 1 wt.% achieving a thickness of 3.99 ± 0.16 mm, closest to the target thickness of 4 mm, while 0.5 wt.% ZnO samples exhibited the lowest deviation in average thickness (±0.03 mm). Tensile stress in digital light processed (DLP) composites with ZnO remained consistent, ranging from 23.29 MPa (1 wt.%) to 25.93 MPa (0.5 wt.%), with an increase in ZnO concentration causing a reduction in tensile stress to 24.04 MPa and a decrease in the elastic modulus to 2001 MPa at 2 wt.% ZnO. The produced DLP samples, with their good corrosion resistance in alkaline environments, are well-suited for applications as protective coatings on tank walls. Customized DLP techniques can enable their effective use as structural or functional elements, such as in Portland cement concrete walls, floors and ceilings for enhanced durability and performance.

The widespread use of epoxy resin (ER) in industry, owing to its excellent properties, aligns with the global shift toward greener resources and energy-efficient solutions, where utilizing metal oxides in 3D printed polymer parts can offer extended functionalities across various industries. ZnO concentrations in polyurethane acrylate composites impacted adhesion and thickness of DLP samples, with 1 wt.% achieving a thickness of 3.99±0.16 mm, closest to the target thickness of 4 mm, while 0.5 wt.% ZnO samples exhibited the lowest deviation in average thickness (±0.03 mm). Tensile strength in digital light processed (DLP) composites with ZnO remained consistent, ranging from 23.29 MPa (1 wt.%) to 25.93 MPa (0.5 wt.%), with an increase in ZnO concentration causing a reduction in tensile strength to 24.04 MPa and a decrease in the elastic modulus to 2001 MPa at 2 wt.% ZnO. The produced DLP samples, with their good corrosion resistance in alkaline environments, are well-suited for applications as protective coatings on tank walls. Customized DLP techniques can enable their effective use as structural or functional elements, such as in Portland cement concrete walls, floors and ceilings for enhanced durability and performance.