You are quite right, seems like there are unbreakable matrices that require chemical action: https://www.jsr.org/hs/index.php/path/article/download/4787/2180/3

You are quite right, seems like there are unbreakable matrices that require chemical action: https://www.jsr.org/hs/index.php/path/article/download/4787/2180/36260 https://www.jsr.org/hs/index.php/path/article/download/4787/... Suitable chemical methods: https://www.sciencedirect.com/science/article/abs/pii/S0141813018312261 https://www.sciencedirect.com/science/article/abs/pii/S01418... https://pmc.ncbi.nlm.nih.gov/articles/PMC10157874/ https://pmc.ncbi.nlm.nih.gov/articles/PMC10157874/