Effects of coating ageing on the acoustic properties of Norway spruce (Picea abies)

Straže, Aleš (author), Žigon, Jure (author), Pavlič, Matjaž (author)

Norway spruce (Picea abies L. Karst) wood is a preferred resonance material for musical instruments, but the surface coatings used to protect it also alter its acoustic behaviour. In this study, the effects of nitrocellulose and polyurethane coatings on spruce lamellas during an ageing period of 300 days were investigated. Gloss, hardness, impact resistance, resonance frequencies, vibration damping (tan δ) and acoustic conversion efficiency (ACE) were measured. Both coatings initially reduced the resonance frequencies and moduli of elasticity (E), while increasing the tan δ and reducing the ACE, with the nitrocellulose having a greater effect. Ageing led to greater hardness, lower tan δ and improved ACE, which can be attributed to the progressive curing of the coatings. The strong correlation between hardness and acoustic parameters suggests that mechanical surface properties may serve as predictors of acoustic effectiveness. Polyurethane maintained acoustic performance better than nitrocellulose, although impact resistance decreased with ageing. These results emphasize the importance of choosing coating systems that balance durability and long-term acoustic requirements in instrument making.

• Language: English
• Keywords: spruce wood, nitrocellulose, polyurethane, acoustic properties, damping, coating properties, coating ageing
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 1-15
• Numbering: Vol. 15, iss. 11, [art. no.] 1264
• PID: 20.500.12556/RUL-175551
• UDC: 630*8
• ISSN on article: 2079-6412
• DOI: 10.3390/coatings15111264
• COBISS.SI-ID: 255614467
• Publication date in RUL: 04.11.2025

Record is a part of a journal

• Title: Coatings
• Shortened title: Coatings
• Publisher: MDPI AG
• ISSN: 2079-6412
• COBISS.SI-ID: 523035673

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: smrekov les, nitroceluloza, poliuretan, akustične lastnosti, dušenje, lastnosti premazov, staranje premazov

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0015-2020
• Name: Les in lignocelulozni kompoziti

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0430-2022
• Name: Gozdno-lesna veriga in podnebne spremembe: prehod v krožno biogospodarstvo